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libtool: minimise forks per invocation under bash.

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* build-aux/general.m4sh (lt_HAVE_PLUSEQ_OP, lt_HAVE_ARITH_OP)
(lt_HAVE_XSI_OPS): Set these without forking a test script when
running under bash, to avoid a few unnecessary forks.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
This commit is contained in:
Gary V. Vaughan 2011-12-08 17:01:56 +07:00
parent 7a2a8f32bb
commit 7d25536e80
1 changed files with 12 additions and 9 deletions
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21
build-aux/general.m4sh
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@ -74,12 +74,21 @@ dirname='s|/[^/]*$||'
basename='s|^.*/||'
# We should try to minimise forks, especially on Windows where they are
# unreasonably slow, so skip the feature probes when bash is being used:
if test set = "${BASH_VERSION+set}"; then
: ${lt_HAVE_ARITH_OP="yes"}
: ${lt_HAVE_XSI_OPS="yes"}
# The += operator was introduced in bash 3.1
test -z "$lt_HAVE_PLUSEQ_OP" \
&& test 3000 -lt "$((${BASH_VERSINFO[0]}*1000 + ${BASH_VERSINFO[1]}))" \
&& lt_HAVE_PLUSEQ_OP=yes
fi
# lt_HAVE_PLUSEQ_OP
# Can be empty, in which case the shell is probed, "yes" if += is useable
# or anything else if += does not work.
# NOTE: You can short-circuit the fork and test on every invocation (e.g.
# on Windows where fork emulations are unreasonably slow) by setting this
# in the environment of this script.
test -z "$lt_HAVE_PLUSEQ_OP" \
&& (eval 'x=a; x+=" b"; test "a b" = "$x"') 2>/dev/null \
&& lt_HAVE_PLUSEQ_OP=yes
@ -117,9 +126,6 @@ fi
# lt_HAVE_ARITH_OP
# Can be empty, in which case the shell is probed, "yes" if $((...)) is
# useable or anything else if it does not work.
# NOTE: You can short-circuit the fork and test on every invocation (e.g.
# on Windows where fork emulations are unreasonably slow) by setting this
# in the environment of this script.
test -z "$lt_HAVE_ARITH_OP" \
&& (eval 'test 2 = $(( 1 + 1 ))') 2>/dev/null \
&& lt_HAVE_ARITH_OP=yes
@ -141,9 +147,6 @@ fi
# lt_HAVE_XSI_OPS
# Can be empty, in which case the shell is probed, "yes" if XSI length
# and matching operators are useable or anything else if they do not work.
# NOTE: You can short-circuit the fork and test on every invocation (e.g.
# on Windows where fork emulations are unreasonably slow) by setting this
# in the environment of this script.
test -z "$lt_HAVE_XSI_OPS" \
&& (eval 'x=a/b/c;
test 5aa/bb/cc = "${#x}${x%%/*}${x%/*}${x#*/}${x##*/}"') 2>/dev/null \