mirror/autoconf
2
0
Fork 0
mirror of git://git.sv.gnu.org/autoconf synced 2025-03-13 14:36:50 +08:00
Code Issues Packages Projects Releases Wiki Activity

AC_PROG_CC: also check whether $CC supports "-c -o" together

Browse Source 
This is for Automake and its 'subdir-object' mode (see automake bug#13378,
in particular <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13378#73>), so
we make the new behavior available only if the special witness macro
'_AM_PROG_CC_C_O_HELPME' is defined (future Automake versions will define
it).  We might decide, at a later date, to make this behaviour public;
but then we'll have to discuss its usefulness and design more in depth,
and if they are agreed upon, adjust the documentation to match, and also
decide what to do with the macro AC_PROG_CC_C_O, with its similar (but
slightly incompatible) semantics; since doing so right now would bring us
off-track (and Automake needs this change *today*, or better, yesterday),
we proceed with this simpler hack.

* lib/autoconf/c.m4 (AC_PROG_CC): Adjust.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>
This commit is contained in:
Stefano Lattarini 2013-01-10 15:14:24 +01:00
parent ddd0bfbb06
commit ce48964f64
1 changed files with 25 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
lib/autoconf/c.m4
View File

@ -490,7 +490,31 @@ _AC_PROG_CC_C11([ac_prog_cc_stdc=c11
ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c89],
[ac_prog_cc_stdc=no
ac_cv_prog_cc_stdc=no])])])
dnl
dnl This is a hook for Automake and its 'subdir-objects' mode, which
dnl needs to know whether $CC supports "-c -o" together or not. See
dnl automake bug#13378, in particular <http://debbugs.gnu.org/13378#73>.
dnl FIXME: there is some code duplication with AC_PROG_CC_C_O here.
m4_ifdef([_AM_PROG_CC_C_O_HELPME],
[set dummy $CC; ac_cc=`AS_ECHO(["$[2]"]) | \
sed 's/[[^a-zA-Z0-9_]]/_/g;s/^[[0-9]]/_/'`
AC_MSG_CHECKING([whether $CC understands -c and -o together])
AC_CACHE_VAL([ac_cv_prog_cc_${ac_cc}_c_o],
[AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
# Make sure it works both with $CC and with simple cc.
# We do the test twice because some compilers refuse to overwrite an
# existing .o file with -o, though they will create one.
ac_try='$CC -c conftest.$ac_ext -o conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
rm -f conftest2.*
if _AC_DO_VAR(ac_try) && test -f conftest2.$ac_objext
then
AC_MSG_RESULT([yes])
eval ac_cv_prog_cc_${ac_cc}_c_o=yes
else
AC_MSG_RESULT([no])
eval ac_cv_prog_cc_${ac_cc}_c_o=no
fi
rm -f core conftest*
])])dnl
AC_LANG_POP(C)dnl
])# AC_PROG_CC