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[PATCH 01/11] compile: avoid AC_PROG_CC messy rewrite
From: |
Stefano Lattarini |
Subject: |
[PATCH 01/11] compile: avoid AC_PROG_CC messy rewrite |
Date: |
Sat, 12 Jan 2013 13:51:54 +0100 |
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 <address@hidden>
---
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
- [PATCH 00/11] Make 'subdir-objects' mandatory, and related cleanups, Stefano Lattarini, 2013/01/12
- [PATCH 05/11] depend: assume '-c' compiler flag always means to produce object files, Stefano Lattarini, 2013/01/12
- [PATCH 01/11] compile: avoid AC_PROG_CC messy rewrite,
Stefano Lattarini <=
- [PATCH 04/11] depend: assume we can always pass "-o" to the C compiler, Stefano Lattarini, 2013/01/12
- [PATCH 03/11] cleanup: having subdir-objects mandatory allow us some simplifications, Stefano Lattarini, 2013/01/12
- [PATCH 06/11] Automake::Language: drop unused fields 'compile_flag' and 'output_flag', Stefano Lattarini, 2013/01/12
- [PATCH 02/11] subdir-objects: enable unconditionally, Stefano Lattarini, 2013/01/12
- [PATCH 09/11] depend2.am: reduce code duplication, Stefano Lattarini, 2013/01/12
- [PATCH 10/11] depend: prefer $(...) over `...` in Cygwin-specific recipes, Stefano Lattarini, 2013/01/12
- [PATCH 07/11] depend2.am: refactor and remove code duplication, Stefano Lattarini, 2013/01/12
- [PATCH 11/11] depend: reduce code duplication, de-uglify make verbose output, Stefano Lattarini, 2013/01/12