mirror of
git://git.sv.gnu.org/autoconf
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* doc/autoconf.texi (Limitations of Builtins): Document `unset'.
(Special Shell Variables): Adjust. (Shellology): New section. Introduce bash and zsh. (Special Shell Variables): Some data on NULLCMD. (Quotation Thumb Rule): Rename as (Quotation Rule of Thumb): this. * acgeneral.m4 (AC_SHELL_UNSET): Remove. (AC_SHELL_UNSETENV): Rename as... (AC_SHELL_UNSET): this. (_AC_INIT_PREPARE_ENVIRONMENT): Prepare bash and zsh. Adjust to AC_SHELL_UNSET.
This commit is contained in:
Akim Demaille
parent
0705110354
commit
3d3d0c48fc
14
ChangeLog
14
ChangeLog
@ -1,3 +1,17 @@
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2000-05-24 Akim Demaille <akim@epita.fr>
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* doc/autoconf.texi (Limitations of Builtins): Document `unset'.
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(Special Shell Variables): Adjust.
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(Shellology): New section. Introduce bash and zsh.
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(Special Shell Variables): Some data on NULLCMD.
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(Quotation Thumb Rule): Rename as
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(Quotation Rule of Thumb): this.
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* acgeneral.m4 (AC_SHELL_UNSET): Remove.
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(AC_SHELL_UNSETENV): Rename as...
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(AC_SHELL_UNSET): this.
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(_AC_INIT_PREPARE_ENVIRONMENT): Prepare bash and zsh.
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Adjust to AC_SHELL_UNSET.
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2000-05-24 Akim Demaille <akim@epita.fr>
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The options --build etc. used to set `$build'. *If*
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35
acgeneral.m4
35
acgeneral.m4
@ -473,19 +473,11 @@ $debug ||
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])# _AC_SHELL_TMPDIR
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# AC_SHELL_UNSET(VAR, [VALUE-IF-UNSET-NOT-SUPPORTED = `'])
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# --------------------------------------------------------
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# AC_SHELL_UNSETENV(VAR, [VALUE-IF-UNSET-NOT-SUPPORTED = `'])
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# -----------------------------------------------------------
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# Try to unset the env VAR, otherwise set it to
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# VALUE-IF-UNSET-NOT-SUPPORTED. `ac_unset' must have been computed.
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define([AC_SHELL_UNSET],
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[$ac_unset $1 || test "${$1+set}" != set || $1=$2])
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# AC_SHELL_UNSETENV(VAR, [VALUE-IF-UNSET-NOT-SUPPORTED = `'])
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# --------------------------------------------------------
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# Try to unset the env VAR, otherwise set it to
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# VALUE-IF-UNSET-NOT-SUPPORTED. `ac_unset' must have been computed.
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define([AC_SHELL_UNSETENV],
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[$ac_unset $1 || test "${$1+set}" != set || $1=$2 && export $1])
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@ -1466,19 +1458,28 @@ fi])dnl
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# _AC_INIT_PREPARE_ENVIRONMENT
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# ----------------------------
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# Tune the envvar we depend upon: IFS, NLS.
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# Tune the behavior of the shell.
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define([_AC_INIT_PREPARE_ENVIRONMENT],
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[if (unset FOO) >/dev/null 2>&1; then
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[# Be Bourne compatible
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if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
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emulate sh
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NULLCMD=:
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elif test -n "${BASH_VERSION+set}" && (set -o posix) >/dev/null 2>&1; then
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set -o posix
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fi
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# Support unset when possible.
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if (unset FOO) >/dev/null 2>&1; then
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ac_unset=unset
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else
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ac_unset=false
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fi
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# NLS nuisances.
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AC_SHELL_UNSETENV([LANG], [C])
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AC_SHELL_UNSETENV([LC_ALL], [C])
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AC_SHELL_UNSETENV([LC_CTYPE], [C])
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AC_SHELL_UNSETENV([LC_MESSAGES], [C])
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AC_SHELL_UNSET([LANG], [C])
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AC_SHELL_UNSET([LC_ALL], [C])
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AC_SHELL_UNSET([LC_CTYPE], [C])
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AC_SHELL_UNSET([LC_MESSAGES], [C])
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# IFS
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# We need space, tab and new line, in precisely that order.
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@ -1487,7 +1488,7 @@ ac_nl='
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IFS=" $ac_nl"
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# CDPATH.
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AC_SHELL_UNSETENV([CDPATH], [:])
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AC_SHELL_UNSET([CDPATH], [:])
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])
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1
aclocal.m4
vendored
1
aclocal.m4
vendored
@ -2,3 +2,4 @@ m4_include([m4/init.m4])
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m4_include([m4/missing.m4])
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m4_include([m4/sanity.m4])
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m4_include([m4/atconfig.m4])
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m4_include([m4/m4.m4])
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105
configure
vendored
105
configure
vendored
@ -111,9 +111,9 @@ do
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bindir=$ac_optarg ;;
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-build | --build | --buil | --bui | --bu)
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ac_prev=build ;;
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ac_prev=build_alias ;;
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-build=* | --build=* | --buil=* | --bui=* | --bu=*)
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build=$ac_optarg ;;
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build_alias=$ac_optarg ;;
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-cache-file | --cache-file | --cache-fil | --cache-fi \
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| --cache-f | --cache- | --cache | --cach | --cac | --ca | --c)
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@ -175,10 +175,10 @@ do
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-host | --host | --hos | --ho)
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cross_compiling=yes
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ac_prev=host ;;
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ac_prev=host_alias ;;
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-host=* | --host=* | --hos=* | --ho=*)
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cross_compiling=yes
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host=$ac_optarg ;;
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host_alias=$ac_optarg ;;
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-includedir | --includedir | --includedi | --included | --include \
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| --includ | --inclu | --incl | --inc)
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@ -314,9 +314,9 @@ do
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sysconfdir=$ac_optarg ;;
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-target | --target | --targe | --targ | --tar | --ta | --t)
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ac_prev=target ;;
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ac_prev=target_alias ;;
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-target=* | --target=* | --targe=* | --targ=* | --tar=* | --ta=* | --t=*)
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target=$ac_optarg ;;
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target_alias=$ac_optarg ;;
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-v | -verbose | --verbose | --verbos | --verbo | --verb)
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verbose=yes ;;
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@ -383,7 +383,7 @@ Try \`configure --help' for more information." >&2; exit 1; }
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*[^-a-zA-Z0-9.]*) echo "configure: WARNING: invalid host type: $ac_option" >&2;;
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esac
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echo "configure: WARNING: you should use --build, --host, --target" >&2
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: ${build=$ac_option} ${host=$ac_option} ${target=$ac_option}
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: ${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}
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;;
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esac
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@ -407,6 +407,12 @@ do
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esac
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done
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# There might be people who depend on the old broken behavior: `$host'
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# used to hold the argument of --host etc.
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build=$build_alias
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host=$host_alias
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target=$target_alias
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# Find the source files, if location was not specified.
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if test -z "$srcdir"; then
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ac_srcdir_defaulted=yes
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@ -546,6 +552,15 @@ gives unlimited permission to copy, distribute and modify it.
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EOF
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exit 0
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fi
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# Be Bourne compatible
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if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
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emulate sh
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NULLCMD=:
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elif test -n "${BASH_VERSION+set}" && (set -o posix) >/dev/null 2>&1; then
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set -o posix
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fi
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# Support unset when possible.
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if (unset FOO) >/dev/null 2>&1; then
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ac_unset=unset
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else
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@ -694,7 +709,7 @@ ac_configure="$SHELL $ac_aux_dir/configure" # This should be Cygnus configure.
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# AFS /usr/afsws/bin/install, which mishandles nonexistent args
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# SVR4 /usr/ucb/install, which tries to use the nonexistent group "staff"
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# ./install, which can be erroneously created by make from ./install.sh.
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echo "configure:610: checking for a BSD compatible install" >&5
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echo "configure:623: checking for a BSD compatible install" >&5
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echo $ECHO_N "checking for a BSD compatible install... $ECHO_C" >&6
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if test -z "$INSTALL"; then
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if test "${ac_cv_path_install+set}" = set; then
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@ -741,7 +756,7 @@ fi
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INSTALL=$ac_install_sh
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fi
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fi
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echo "configure:656: result: $INSTALL" >&5
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echo "configure:669: result: $INSTALL" >&5
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echo "${ECHO_T}$INSTALL" >&6
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# Use test -z because SunOS4 sh mishandles braces in ${var-val}.
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@ -752,7 +767,7 @@ test -z "$INSTALL_SCRIPT" && INSTALL_SCRIPT='${INSTALL}'
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test -z "$INSTALL_DATA" && INSTALL_DATA='${INSTALL} -m 644'
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echo "configure:663: checking whether build environment is sane" >&5
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echo "configure:676: checking whether build environment is sane" >&5
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echo $ECHO_N "checking whether build environment is sane... $ECHO_C" >&6
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# Just in case
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sleep 1
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@ -789,7 +804,7 @@ else
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Check your system clock" >&2; exit 1; }
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fi
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rm -f conftest*
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echo "configure:698: result: yes" >&5
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echo "configure:711: result: yes" >&5
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echo "${ECHO_T}yes" >&6
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if test "$program_transform_name" = s,x,x,; then
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program_transform_name=
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@ -810,7 +825,7 @@ test "$program_suffix" != NONE &&
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# sed with no file args requires a program.
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test -z "$program_transform_name" && program_transform_name="s,x,x,"
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echo "configure:717: checking whether ${MAKE-make} sets \${MAKE}" >&5
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echo "configure:730: checking whether ${MAKE-make} sets \${MAKE}" >&5
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echo $ECHO_N "checking whether ${MAKE-make} sets \${MAKE}... $ECHO_C" >&6
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set dummy ${MAKE-make}; ac_make=`echo "$2" | sed 'y%./+-%__p_%'`
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if eval "test \"\${ac_cv_prog_make_${ac_make}_set+set}\" = set"; then
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@ -830,11 +845,11 @@ fi
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rm -f conftestmake
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fi
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if eval "test \"`echo '$ac_cv_prog_make_'${ac_make}_set`\" = yes"; then
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echo "configure:737: result: yes" >&5
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echo "configure:750: result: yes" >&5
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echo "${ECHO_T}yes" >&6
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SET_MAKE=
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else
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echo "configure:741: result: no" >&5
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echo "configure:754: result: no" >&5
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echo "${ECHO_T}no" >&6
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SET_MAKE="MAKE=${MAKE-make}"
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fi
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@ -856,78 +871,78 @@ cat >>confdefs.h <<EOF
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EOF
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missing_dir=`cd $ac_aux_dir && pwd`
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echo "configure:757: checking for working aclocal" >&5
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echo "configure:770: checking for working aclocal" >&5
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echo $ECHO_N "checking for working aclocal... $ECHO_C" >&6
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# Run test in a subshell; some versions of sh will print an error if
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# an executable is not found, even if stderr is redirected.
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# Redirect stdin to placate older versions of autoconf. Sigh.
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if (aclocal --version) < /dev/null > /dev/null 2>&1; then
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ACLOCAL=aclocal
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echo "configure:764: result: found" >&5
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echo "configure:777: result: found" >&5
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echo "${ECHO_T}found" >&6
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else
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ACLOCAL="$missing_dir/missing aclocal"
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echo "configure:768: result: missing" >&5
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echo "configure:781: result: missing" >&5
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echo "${ECHO_T}missing" >&6
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fi
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echo "configure:771: checking for working autoconf" >&5
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echo "configure:784: checking for working autoconf" >&5
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echo $ECHO_N "checking for working autoconf... $ECHO_C" >&6
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# Run test in a subshell; some versions of sh will print an error if
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# an executable is not found, even if stderr is redirected.
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# Redirect stdin to placate older versions of autoconf. Sigh.
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if (autoconf --version) < /dev/null > /dev/null 2>&1; then
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AUTOCONF=autoconf
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echo "configure:778: result: found" >&5
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echo "configure:791: result: found" >&5
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echo "${ECHO_T}found" >&6
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else
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AUTOCONF="$missing_dir/missing autoconf"
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echo "configure:782: result: missing" >&5
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echo "configure:795: result: missing" >&5
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echo "${ECHO_T}missing" >&6
|
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fi
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|
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echo "configure:785: checking for working automake" >&5
|
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echo "configure:798: checking for working automake" >&5
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echo $ECHO_N "checking for working automake... $ECHO_C" >&6
|
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# Run test in a subshell; some versions of sh will print an error if
|
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# an executable is not found, even if stderr is redirected.
|
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# Redirect stdin to placate older versions of autoconf. Sigh.
|
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if (automake --version) < /dev/null > /dev/null 2>&1; then
|
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AUTOMAKE=automake
|
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echo "configure:792: result: found" >&5
|
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echo "configure:805: result: found" >&5
|
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echo "${ECHO_T}found" >&6
|
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else
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AUTOMAKE="$missing_dir/missing automake"
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echo "configure:796: result: missing" >&5
|
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echo "configure:809: result: missing" >&5
|
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echo "${ECHO_T}missing" >&6
|
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fi
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|
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echo "configure:799: checking for working autoheader" >&5
|
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echo "configure:812: checking for working autoheader" >&5
|
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echo $ECHO_N "checking for working autoheader... $ECHO_C" >&6
|
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# Run test in a subshell; some versions of sh will print an error if
|
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# an executable is not found, even if stderr is redirected.
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# Redirect stdin to placate older versions of autoconf. Sigh.
|
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if (autoheader --version) < /dev/null > /dev/null 2>&1; then
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AUTOHEADER=autoheader
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echo "configure:806: result: found" >&5
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echo "configure:819: result: found" >&5
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echo "${ECHO_T}found" >&6
|
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else
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AUTOHEADER="$missing_dir/missing autoheader"
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echo "configure:810: result: missing" >&5
|
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echo "configure:823: result: missing" >&5
|
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echo "${ECHO_T}missing" >&6
|
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fi
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|
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echo "configure:813: checking for working makeinfo" >&5
|
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echo "configure:826: checking for working makeinfo" >&5
|
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echo $ECHO_N "checking for working makeinfo... $ECHO_C" >&6
|
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# Run test in a subshell; some versions of sh will print an error if
|
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# an executable is not found, even if stderr is redirected.
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# Redirect stdin to placate older versions of autoconf. Sigh.
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if (makeinfo --version) < /dev/null > /dev/null 2>&1; then
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MAKEINFO=makeinfo
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echo "configure:820: result: found" >&5
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echo "configure:833: result: found" >&5
|
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echo "${ECHO_T}found" >&6
|
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else
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MAKEINFO="$missing_dir/missing makeinfo"
|
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echo "configure:824: result: missing" >&5
|
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echo "configure:837: result: missing" >&5
|
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echo "${ECHO_T}missing" >&6
|
||||
fi
|
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|
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@ -942,7 +957,7 @@ for ac_prog in gm4 gnum4 m4
|
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do
|
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# Extract the first word of "$ac_prog", so it can be a program name with args.
|
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set dummy $ac_prog; ac_word=$2
|
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echo "configure:837: checking for $ac_word" >&5
|
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echo "configure:850: checking for $ac_word" >&5
|
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echo $ECHO_N "checking for $ac_word... $ECHO_C" >&6
|
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if test "${ac_cv_path_M4+set}" = set; then
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echo $ECHO_N "(cached) $ECHO_C" >&6
|
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@ -967,10 +982,10 @@ esac
|
||||
fi
|
||||
M4=$ac_cv_path_M4
|
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if test -n "$M4"; then
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echo "configure:862: result: $M4" >&5
|
||||
echo "configure:875: result: $M4" >&5
|
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echo "${ECHO_T}$M4" >&6
|
||||
else
|
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echo "configure:865: result: no" >&5
|
||||
echo "configure:878: result: no" >&5
|
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echo "${ECHO_T}no" >&6
|
||||
fi
|
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|
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@ -978,7 +993,7 @@ test -n "$M4" && break
|
||||
done
|
||||
test -n "$M4" || M4="m4"
|
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|
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echo "configure:871: checking whether m4 supports frozen files" >&5
|
||||
echo "configure:884: checking whether m4 supports frozen files" >&5
|
||||
echo $ECHO_N "checking whether m4 supports frozen files... $ECHO_C" >&6
|
||||
if test "${ac_cv_prog_gnu_m4+set}" = set; then
|
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echo $ECHO_N "(cached) $ECHO_C" >&6
|
||||
@ -990,7 +1005,7 @@ if test x"$M4" != x; then
|
||||
esac
|
||||
fi
|
||||
fi
|
||||
echo "configure:883: result: $ac_cv_prog_gnu_m4" >&5
|
||||
echo "configure:896: result: $ac_cv_prog_gnu_m4" >&5
|
||||
echo "${ECHO_T}$ac_cv_prog_gnu_m4" >&6
|
||||
if test x"$ac_cv_prog_gnu_m4" != xyes; then
|
||||
{ echo "configure: error: GNU m4 1.4 is required" >&2; exit 1; }
|
||||
@ -1003,7 +1018,7 @@ for ac_prog in mawk gawk nawk awk
|
||||
do
|
||||
# Extract the first word of "$ac_prog", so it can be a program name with args.
|
||||
set dummy $ac_prog; ac_word=$2
|
||||
echo "configure:895: checking for $ac_word" >&5
|
||||
echo "configure:908: checking for $ac_word" >&5
|
||||
echo $ECHO_N "checking for $ac_word... $ECHO_C" >&6
|
||||
if test "${ac_cv_prog_AWK+set}" = set; then
|
||||
echo $ECHO_N "(cached) $ECHO_C" >&6
|
||||
@ -1028,10 +1043,10 @@ fi
|
||||
fi
|
||||
AWK=$ac_cv_prog_AWK
|
||||
if test -n "$AWK"; then
|
||||
echo "configure:920: result: $AWK" >&5
|
||||
echo "configure:933: result: $AWK" >&5
|
||||
echo "${ECHO_T}$AWK" >&6
|
||||
else
|
||||
echo "configure:923: result: no" >&5
|
||||
echo "configure:936: result: no" >&5
|
||||
echo "${ECHO_T}no" >&6
|
||||
fi
|
||||
|
||||
@ -1039,25 +1054,25 @@ test -n "$AWK" && break
|
||||
done
|
||||
|
||||
# Generating man pages.
|
||||
echo "configure:929: checking for working help2man" >&5
|
||||
echo "configure:942: checking for working help2man" >&5
|
||||
echo $ECHO_N "checking for working help2man... $ECHO_C" >&6
|
||||
# Run test in a subshell; some versions of sh will print an error if
|
||||
# an executable is not found, even if stderr is redirected.
|
||||
# Redirect stdin to placate older versions of autoconf. Sigh.
|
||||
if (help2man --version) < /dev/null > /dev/null 2>&1; then
|
||||
HELP2MAN=help2man
|
||||
echo "configure:936: result: found" >&5
|
||||
echo "configure:949: result: found" >&5
|
||||
echo "${ECHO_T}found" >&6
|
||||
else
|
||||
HELP2MAN="\${SHELL} \${top_srcdir}/missing help2man"
|
||||
echo "configure:940: result: missing" >&5
|
||||
echo "configure:953: result: missing" >&5
|
||||
echo "${ECHO_T}missing" >&6
|
||||
fi
|
||||
|
||||
# We use a path for perl so the #! line in autoscan will work.
|
||||
# Extract the first word of "perl", so it can be a program name with args.
|
||||
set dummy perl; ac_word=$2
|
||||
echo "configure:946: checking for $ac_word" >&5
|
||||
echo "configure:959: checking for $ac_word" >&5
|
||||
echo $ECHO_N "checking for $ac_word... $ECHO_C" >&6
|
||||
if test "${ac_cv_path_PERL+set}" = set; then
|
||||
echo $ECHO_N "(cached) $ECHO_C" >&6
|
||||
@ -1083,10 +1098,10 @@ esac
|
||||
fi
|
||||
PERL=$ac_cv_path_PERL
|
||||
if test -n "$PERL"; then
|
||||
echo "configure:972: result: $PERL" >&5
|
||||
echo "configure:985: result: $PERL" >&5
|
||||
echo "${ECHO_T}$PERL" >&6
|
||||
else
|
||||
echo "configure:975: result: no" >&5
|
||||
echo "configure:988: result: no" >&5
|
||||
echo "${ECHO_T}no" >&6
|
||||
fi
|
||||
|
||||
@ -1107,7 +1122,7 @@ fi
|
||||
# AFS /usr/afsws/bin/install, which mishandles nonexistent args
|
||||
# SVR4 /usr/ucb/install, which tries to use the nonexistent group "staff"
|
||||
# ./install, which can be erroneously created by make from ./install.sh.
|
||||
echo "configure:994: checking for a BSD compatible install" >&5
|
||||
echo "configure:1007: checking for a BSD compatible install" >&5
|
||||
echo $ECHO_N "checking for a BSD compatible install... $ECHO_C" >&6
|
||||
if test -z "$INSTALL"; then
|
||||
if test "${ac_cv_path_install+set}" = set; then
|
||||
@ -1154,7 +1169,7 @@ fi
|
||||
INSTALL=$ac_install_sh
|
||||
fi
|
||||
fi
|
||||
echo "configure:1040: result: $INSTALL" >&5
|
||||
echo "configure:1053: result: $INSTALL" >&5
|
||||
echo "${ECHO_T}$INSTALL" >&6
|
||||
|
||||
# Use test -z because SunOS4 sh mishandles braces in ${var-val}.
|
||||
|
||||
@ -253,6 +253,7 @@ Checking Run Time Behavior
|
||||
|
||||
Portable Shell Programming
|
||||
|
||||
* Shellology:: A zoology of shells
|
||||
* Special Shell Variables:: Variables you should not change
|
||||
* Shell Substitutions:: Test and assign
|
||||
* Limitations of Builtins:: Portable use of not so portable /bin/sh
|
||||
@ -283,7 +284,7 @@ Quoting
|
||||
* Active Characters:: Characters that change the behavior of m4
|
||||
* One Macro Call:: Quotation and one macro call
|
||||
* Quotation and Nested Macros:: Macros calling macros
|
||||
* Quotation Thumb Rule:: One parenthesis, one quote
|
||||
* Quotation Rule Of Thumb:: One parenthesis, one quote
|
||||
|
||||
Dependencies Between Macros
|
||||
|
||||
@ -668,7 +669,7 @@ AC_MSG_WARN([[AC_DC stinks --Iron Maiden]])
|
||||
@end example
|
||||
|
||||
You are now able to understand one of the constructs of Autoconf which
|
||||
has continuously been misunderstood... The thumb rule is that
|
||||
has continuously been misunderstood... The rule of thumb is that
|
||||
@emph{whenever you expect macro expansion, expect quote expansion},
|
||||
i.e., expect one level of quotes to be lost. For instance
|
||||
|
||||
@ -4524,23 +4525,54 @@ restriction allows users to start out with a fairly small set of
|
||||
programs and build the rest, avoiding too many interdependencies between
|
||||
packages.
|
||||
|
||||
Some of these external utilities have a portable subset of features, as
|
||||
well; for example, don't rely on @code{ln} having a @samp{-f} option or
|
||||
@code{cat} having any options.
|
||||
Some of these external utilities have a portable subset of features, see
|
||||
@ref{Limitations of Usual Tools}.
|
||||
|
||||
@menu
|
||||
* Shellology:: A zoology of shells
|
||||
* Special Shell Variables:: Variables you should not change
|
||||
* Shell Substitutions:: Test and assign
|
||||
* Limitations of Builtins:: Portable use of not so portable /bin/sh
|
||||
* Limitations of Usual Tools:: Portable use of portable tools
|
||||
@end menu
|
||||
|
||||
@node Special Shell Variables, Shell Substitutions, Portable Shell, Portable Shell
|
||||
@node Shellology, Special Shell Variables, Portable Shell, Portable Shell
|
||||
@subsection Shellology
|
||||
|
||||
There are several families of shells, most prominently the Bourne
|
||||
family and the C shell family which are deeply incompatible. If you
|
||||
want to write portable shell scripts, avoid members of the C shell
|
||||
family.
|
||||
|
||||
Below we describe some of the members of the Bourne shell family.
|
||||
|
||||
@table @asis
|
||||
@item @command{bash}
|
||||
@cindex @command{bash}
|
||||
To detect whether you are running @command{bash}, test if
|
||||
@code{BASH_VERSION} is set. To disable its extensions and require
|
||||
@sc{posix} compatibility, run @samp{set -o posix}. @xref{Bash POSIX
|
||||
Mode,, Bash @sc{posix} Mode, bash, The GNU Bash Reference Manual}, for
|
||||
details.
|
||||
|
||||
@item @command{zsh}
|
||||
@cindex @command{zsh}
|
||||
To detect whether you are running @command{zsh}, test if
|
||||
@code{ZSH_VERSION} is set. By default @command{zsh} is @emph{not}
|
||||
compatible with the Bourne shell: you have to run @samp{emulate sh} and
|
||||
set @code{NULLCMD} to @samp{:}. @xref{Compatibility,, Compatibility,
|
||||
zsh, The Z Shell Manual}, for details.
|
||||
@end table
|
||||
|
||||
|
||||
@node Special Shell Variables, Shell Substitutions, Shellology, Portable Shell
|
||||
@subsection Special Shell Variables
|
||||
|
||||
Some shell variables shall not be used. Since currently Autoconf does
|
||||
not use @code{unset}, there are some variables which need some specific
|
||||
values to disable the features they control.
|
||||
Some shell variables shall not be used or have a deep influence on the
|
||||
behavior of the shell. In order to recover a sane behavior from the
|
||||
shell, some variables should be unset, but @command{unset} is not
|
||||
portable (@pxref{Limitations of Builtins}) and a fall back value is
|
||||
needed. We list these values below.
|
||||
|
||||
@c Alphabetical order, case insensitive, `A' before `a'.
|
||||
@table @code
|
||||
@ -4577,7 +4609,9 @@ bash-2.02 % (CDPATH=.: cd foo)
|
||||
@end example
|
||||
|
||||
Therefore a portable solution to neutralize @samp{CDPATH} is
|
||||
@samp{CDPATH=$@{ZSH_VERSION+.@}:}.
|
||||
@samp{CDPATH=$@{ZSH_VERSION+.@}:}. Note that since @command{zsh}
|
||||
support @command{unset}, you may unset @samp{CDPATH} using @samp{:} as a
|
||||
fall back, see @ref{Limitations of Builtins}.
|
||||
|
||||
@item LANG
|
||||
@itemx LC_ALL
|
||||
@ -4600,6 +4634,14 @@ test "$@{LC_CTYPE+set@}" = set && LC_CTYPE=C && export LC_CTYPE
|
||||
test "$@{LC_MESSAGES+set@}" = set && LC_MESSAGES=C && export LC_MESSAGES
|
||||
@end example
|
||||
|
||||
@item NULLCMD
|
||||
@evindex NULLCMD
|
||||
When executing the command @samp{>foo}, @command{zsh} executes
|
||||
@samp{$NULLCMD >foo}. The Bourne shell considers @code{NULLCMD} is
|
||||
@samp{:}, while @command{zsh}, even in Bourne shell compatibility mode,
|
||||
sets @code{NULLCMD} to @samp{cat}. If you forgot to set @code{NULLCMD},
|
||||
your script might be suspended waiting for data on its standard input.
|
||||
|
||||
@item status
|
||||
@evindex status
|
||||
This variable is an alias to @samp{$?} for @code{zsh} (at least 3.1.6),
|
||||
@ -4806,6 +4848,27 @@ case $ac_feature in
|
||||
*[^-a-zA-Z0-9_]*) @var{action};;
|
||||
esac
|
||||
@end example
|
||||
|
||||
@item @command{unset}
|
||||
@cindex @command{unset}
|
||||
You cannot assume the support of @command{unset}, nevertheless, because
|
||||
it is extremely useful to disable embarrassing variables such as
|
||||
@code{CDPATH} or @code{LANG}, you can test for its existence, and use
|
||||
it @emph{provided} you give a neutralizing value when @command{unset} is
|
||||
not supported:
|
||||
|
||||
@example
|
||||
if (unset FOO) >/dev/null 2>&1; then
|
||||
unset=unset
|
||||
else
|
||||
unset=false
|
||||
fi
|
||||
$unset CDPATH || CDPATH=:
|
||||
@end example
|
||||
|
||||
@xref{Special Shell Variables}, for some neutralizing values. Also, see
|
||||
@ref{Limitations of Builtins}, documentation of @command{export}, for
|
||||
the case of environment variables.
|
||||
@end table
|
||||
|
||||
@node Limitations of Usual Tools, , Limitations of Builtins, Portable Shell
|
||||
@ -4815,6 +4878,10 @@ The small set of tools you can expect to find on any machine can still
|
||||
find some limitations you should be aware of.
|
||||
|
||||
@table @asis
|
||||
@item @command{cat}
|
||||
@cindex @command{cat}
|
||||
Don't rely on any option.
|
||||
|
||||
@item @command{egrep}
|
||||
@cindex @command{egrep}
|
||||
The empty alternative is not portable, use @samp{?} instead. For
|
||||
@ -4845,6 +4912,10 @@ honor the last pattern (eg., IRIX 6.5 and Solaris 2.5.1). Anyway,
|
||||
Stardent Vistra SVR4 @code{grep} lacks @samp{-e}... Instead, use
|
||||
alternation and @code{egrep}.
|
||||
|
||||
@item @command{ln}
|
||||
@cindex @command{ln}
|
||||
Don't rely on @code{ln} having a @samp{-f} option.
|
||||
|
||||
@item @command{sed}
|
||||
@cindex @command{sed}
|
||||
@code{sed} scripts should not use branch labels longer than 8 characters
|
||||
@ -5472,14 +5543,14 @@ macro does. For example, @code{AC_PATH_X} has internal macros
|
||||
The most common brokenness of existing macros is an improper quotation.
|
||||
This section, which users of Autoconf can skip, but which macro writers
|
||||
@emph{must} read, first justifies the quotation scheme which was chosen
|
||||
for Autoconf, and ends with the thumb rules. Understanding the former
|
||||
for Autoconf, and ends with the rule of thumb. Understanding the former
|
||||
helps following the latter.
|
||||
|
||||
@menu
|
||||
* Active Characters:: Characters that change the behavior of m4
|
||||
* One Macro Call:: Quotation and one macro call
|
||||
* Quotation and Nested Macros:: Macros calling macros
|
||||
* Quotation Thumb Rule:: One parenthesis, one quote
|
||||
* Quotation Rule Of Thumb:: One parenthesis, one quote
|
||||
@end menu
|
||||
|
||||
@node Active Characters, One Macro Call, Quoting, Quoting
|
||||
@ -5609,7 +5680,7 @@ With this in mind, we can explore the cases where macros invoke
|
||||
macros...
|
||||
|
||||
|
||||
@node Quotation and Nested Macros, Quotation Thumb Rule, One Macro Call, Quoting
|
||||
@node Quotation and Nested Macros, Quotation Rule Of Thumb, One Macro Call, Quoting
|
||||
@subsection Quotation and Nested Macros
|
||||
|
||||
The examples below use the following macros:
|
||||
@ -5737,10 +5808,10 @@ its users to leave their macro calls unquoted, which is dangerous.
|
||||
Also, because it behaves differently from the other macro, it's an
|
||||
exception, which we are avoiding in Autoconf.
|
||||
|
||||
@node Quotation Thumb Rule, , Quotation and Nested Macros, Quoting
|
||||
@subsection Quotation Thumb Rule
|
||||
@node Quotation Rule Of Thumb, , Quotation and Nested Macros, Quoting
|
||||
@subsection Quotation Rule Of Thumb
|
||||
|
||||
To conclude, the quotation thumb rules are:
|
||||
To conclude, the quotation rule of thumb is:
|
||||
|
||||
@center @emph{One pair of quotes per pair of parentheses.}
|
||||
|
||||
|
||||
@ -473,19 +473,11 @@ $debug ||
|
||||
])# _AC_SHELL_TMPDIR
|
||||
|
||||
|
||||
# AC_SHELL_UNSET(VAR, [VALUE-IF-UNSET-NOT-SUPPORTED = `'])
|
||||
# --------------------------------------------------------
|
||||
# AC_SHELL_UNSETENV(VAR, [VALUE-IF-UNSET-NOT-SUPPORTED = `'])
|
||||
# -----------------------------------------------------------
|
||||
# Try to unset the env VAR, otherwise set it to
|
||||
# VALUE-IF-UNSET-NOT-SUPPORTED. `ac_unset' must have been computed.
|
||||
define([AC_SHELL_UNSET],
|
||||
[$ac_unset $1 || test "${$1+set}" != set || $1=$2])
|
||||
|
||||
|
||||
# AC_SHELL_UNSETENV(VAR, [VALUE-IF-UNSET-NOT-SUPPORTED = `'])
|
||||
# --------------------------------------------------------
|
||||
# Try to unset the env VAR, otherwise set it to
|
||||
# VALUE-IF-UNSET-NOT-SUPPORTED. `ac_unset' must have been computed.
|
||||
define([AC_SHELL_UNSETENV],
|
||||
[$ac_unset $1 || test "${$1+set}" != set || $1=$2 && export $1])
|
||||
|
||||
|
||||
@ -1466,19 +1458,28 @@ fi])dnl
|
||||
|
||||
# _AC_INIT_PREPARE_ENVIRONMENT
|
||||
# ----------------------------
|
||||
# Tune the envvar we depend upon: IFS, NLS.
|
||||
# Tune the behavior of the shell.
|
||||
define([_AC_INIT_PREPARE_ENVIRONMENT],
|
||||
[if (unset FOO) >/dev/null 2>&1; then
|
||||
[# Be Bourne compatible
|
||||
if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
|
||||
emulate sh
|
||||
NULLCMD=:
|
||||
elif test -n "${BASH_VERSION+set}" && (set -o posix) >/dev/null 2>&1; then
|
||||
set -o posix
|
||||
fi
|
||||
|
||||
# Support unset when possible.
|
||||
if (unset FOO) >/dev/null 2>&1; then
|
||||
ac_unset=unset
|
||||
else
|
||||
ac_unset=false
|
||||
fi
|
||||
|
||||
# NLS nuisances.
|
||||
AC_SHELL_UNSETENV([LANG], [C])
|
||||
AC_SHELL_UNSETENV([LC_ALL], [C])
|
||||
AC_SHELL_UNSETENV([LC_CTYPE], [C])
|
||||
AC_SHELL_UNSETENV([LC_MESSAGES], [C])
|
||||
AC_SHELL_UNSET([LANG], [C])
|
||||
AC_SHELL_UNSET([LC_ALL], [C])
|
||||
AC_SHELL_UNSET([LC_CTYPE], [C])
|
||||
AC_SHELL_UNSET([LC_MESSAGES], [C])
|
||||
|
||||
# IFS
|
||||
# We need space, tab and new line, in precisely that order.
|
||||
@ -1487,7 +1488,7 @@ ac_nl='
|
||||
IFS=" $ac_nl"
|
||||
|
||||
# CDPATH.
|
||||
AC_SHELL_UNSETENV([CDPATH], [:])
|
||||
AC_SHELL_UNSET([CDPATH], [:])
|
||||
])
|
||||
|
||||
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user