Commit 5865450decd13275b2bde064bd4a0f79bca6dba2
2021-03-23T19:50:09
Update ax_cc_maxopt m4 macro (#617) Keeps libffi's specific changes (https://github.com/libffi/libffi/commit/cec3a3a201f17a7f018f25e1a0917bd5206e5a5a#diff-2396a1256ac4b1c6849c931ddb8018bdd984bb2383be21bb819a33b95d8d603f) and updates to the latest ax_cc_maxopt.m4 (http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=commit;h=73ee1b396c21062ee8eeb8721ba5323322110fb5): ax_cc_maxopt.m4: retain setting of CFLAGS by configure AX_CC_MAXOPT checks whether CFLAGS was set by the user; if so, the user’s setting is respected. This behavior is retained, of course. However, AX_CC_MAXOPT was then setting CFLAGS="". This overrode the default setting by configure, which usually includes -g. Hence, if CFLAGS was not set by the user, retain the default setting, to preserve the ability to debug. A typical default setting from configure is "-g -O2". This means that AX_CC_MAXOPT might typically set CFLAGS to "-g -O2 -O3". This is fine, because the later -O3 will override the earlier -O2. (The only assumption is that all compilers that AX_CC_MAXOPT knows behave in this sane way.)
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diff --git a/m4/ax_cc_maxopt.m4 b/m4/ax_cc_maxopt.m4
index 9e7f1ee..027b6d8 100644
--- a/m4/ax_cc_maxopt.m4
+++ b/m4/ax_cc_maxopt.m4
@@ -55,7 +55,7 @@
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
-#serial 17
+#serial 18
AC_DEFUN([AX_CC_MAXOPT],
[
@@ -68,19 +68,18 @@ AC_ARG_ENABLE(portable-binary, [AS_HELP_STRING([--enable-portable-binary], [disa
# Try to determine "good" native compiler flags if none specified via CFLAGS
if test "$ac_test_CFLAGS" != "set"; then
- CFLAGS=""
case $ax_cv_c_compiler_vendor in
- dec) CFLAGS="-newc -w0 -O5 -ansi_alias -ansi_args -fp_reorder -tune host"
+ dec) CFLAGS="$CFLAGS -newc -w0 -O5 -ansi_alias -ansi_args -fp_reorder -tune host"
if test "x$acx_maxopt_portable" = xno; then
CFLAGS="$CFLAGS -arch host"
fi;;
- sun) CFLAGS="-native -fast -xO5 -dalign"
+ sun) CFLAGS="$CFLAGS -native -fast -xO5 -dalign"
if test "x$acx_maxopt_portable" = xyes; then
CFLAGS="$CFLAGS -xarch=generic"
fi;;
- hp) CFLAGS="+Oall +Optrs_ansi +DSnative"
+ hp) CFLAGS="$CFLAGS +Oall +Optrs_ansi +DSnative"
if test "x$acx_maxopt_portable" = xyes; then
CFLAGS="$CFLAGS +DAportable"
fi;;
@@ -91,8 +90,8 @@ if test "$ac_test_CFLAGS" != "set"; then
xlc_opt="-qtune=auto"
fi
AX_CHECK_COMPILE_FLAG($xlc_opt,
- CFLAGS="-O3 -qansialias -w $xlc_opt",
- [CFLAGS="-O3 -qansialias -w"
+ CFLAGS="$CFLAGS -O3 -qansialias -w $xlc_opt",
+ [CFLAGS="$CFLAGS -O3 -qansialias -w"
echo "******************************************************"
echo "* You seem to have the IBM C compiler. It is *"
echo "* recommended for best performance that you use: *"
@@ -105,7 +104,7 @@ if test "$ac_test_CFLAGS" != "set"; then
echo "******************************************************"])
;;
- intel) CFLAGS="-O3 -ansi_alias"
+ intel) CFLAGS="$CFLAGS -O3 -ansi_alias"
if test "x$acx_maxopt_portable" = xno; then
icc_archflag=unknown
icc_flags=""
@@ -146,7 +145,7 @@ if test "$ac_test_CFLAGS" != "set"; then
gnu)
# default optimization flags for gcc on all systems
- CFLAGS="-O3 -fomit-frame-pointer"
+ CFLAGS="$CFLAGS -O3 -fomit-frame-pointer"
# -malign-double for x86 systems
# libffi local change -- don't align double, as it changes the ABI
@@ -164,7 +163,7 @@ if test "$ac_test_CFLAGS" != "set"; then
microsoft)
# default optimization flags for MSVC opt builds
- CFLAGS="-O2"
+ CFLAGS="$CFLAGS -O2"
;;
esac
@@ -176,7 +175,7 @@ if test "$ac_test_CFLAGS" != "set"; then
echo "* (otherwise, a default of CFLAGS=-O3 will be used) *"
echo "********************************************************"
echo ""
- CFLAGS="-O3"
+ CFLAGS="$CFLAGS -O3"
fi
AX_CHECK_COMPILE_FLAG($CFLAGS, [], [
@@ -187,7 +186,6 @@ if test "$ac_test_CFLAGS" != "set"; then
echo "* Use ./configure CFLAGS=... to specify your own flags *"
echo "********************************************************"
echo ""
- CFLAGS=""
])
fi