Instead, only touch up AC_PROG_CC to distribute the 'compile' script and to rewrite $CC if a losing compiler is detected. We can do so because Autoconf 2.70 (which we now require) has been so kind to implement the features we need (through a private hook made explicitly available to us), in commit v2.69-63-gce48964 of 2013-01-11, "AC_PROG_CC: also check whether $CC supports "-c -o" together": <http://lists.gnu.org/archive/html/autoconf-patches/2013-01/msg00007.html>
* m4/init.m4 (AC_PROG_CC): Simplify, relying on the Autoconf hook. Signed-off-by: Stefano Lattarini <stefano.lattar...@gmail.com> --- m4/init.m4 | 42 ++++++++---------------------------------- 1 file changed, 8 insertions(+), 34 deletions(-) diff --git a/m4/init.m4 b/m4/init.m4 index c5af65c..9316c2c 100644 --- a/m4/init.m4 +++ b/m4/init.m4 @@ -126,42 +126,16 @@ m4_define([_AC_COMPILER_EXEEXT], m4_defn([_AC_COMPILER_EXEEXT])[m4_provide([_AM_COMPILER_EXEEXT])]) dnl We have to redefine AC_PROG_CC to allow our compile rules to use -dnl "-c -o" together also with losing compilers. -dnl FIXME: Add references to the original discussion and bug report. -dnl FIXME: Shameless copy & paste from Autoconf internals, since trying to -dnl play smart among tangles of AC_REQUIRE, m4_defn, m4_provide and -dnl other tricks was proving too difficult, and in the end, likely -dnl more brittle too. And this should anyway be just a temporary -dnl band-aid, until Autoconf provides the semantics and/or hooks we -dnl need (hint hint, nudge nudge) ... +dnl "-c -o" together also with losing compilers. We can do so using +dnl a private hook Autoconf has made available to us (since version +dnl 2.70). AC_DEFUN([AC_PROG_CC], +[AC_REQUIRE([AM_AUX_DIR_EXPAND])]dnl +[AC_REQUIRE_AUX_FILE([compile])]dnl +[m4_define([_AM_PROG_CC_C_O_HELPME], [1])]dnl Activate the private hook. +dnl This must *not* be quoted! m4_defn([AC_PROG_CC]) -[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl -AC_REQUIRE_AUX_FILE([compile])dnl -dnl FIXME The following abomination is expected to disappear in -dnl Automake 1.14. -AC_MSG_CHECKING([whether $CC understands -c and -o together]) -set dummy $CC; am__cc=`AS_ECHO(["$[2]"]) | \ - sed 's/[[^a-zA-Z0-9_]]/_/g;s/^[[0-9]]/_/'` -AC_CACHE_VAL([am_cv_prog_cc_${am__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.$ac_objext -then - eval am_cv_prog_cc_${am__cc}_c_o=yes -else - eval am_cv_prog_cc_${am__cc}_c_o=no -fi -rm -f core conftest* -])dnl -if eval test \"\$am_cv_prog_cc_${am__cc}_c_o\" = yes; then - AC_MSG_RESULT([yes]) -else - AC_MSG_RESULT([no]) +[if eval test \"\$ac_cv_prog_cc_${ac_cc}_c_o\" != yes; then # Losing compiler, so wrap it with the 'compile' script. # FIXME: It is wrong to rewrite CC. # But if we don't then we get into trouble of one sort or another. -- 1.8.1.rc3.192.g2d0029e