Rewrite the CC_CHECK_CFLAGS macro, to be more in style with Autoconf macros, and cache the value. Rewrite also CC_CHECK_WERROR, caching there too. Rename the final variable with the werror flag ($werror -> $cc_cv_werror).

CVS patchset: 8714
CVS date: 2007/03/19 23:02:16

1 files changed, 70 insertions, 33 deletions

diff --git a/m4/attributes.m4 b/m4/attributes.m4
index a83390006..b6118433d 100644
--- a/m4/attributes.m4
+++ b/m4/attributes.m4
@@ -1,37 +1,74 @@
-# Functions to check for attributes support in compiler
+dnl Macros to check the presence of generic (non-typed) symbols.
+dnl Copyright (c) 2006-2007 Diego Pettenò <flameeyes@gmail.com>
+dnl Copyright (c) 2006-2007 xine project
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 2, or (at your option)
+dnl any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program; if not, write to the Free Software
+dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+dnl 02110-1301, USA.
+dnl
+dnl As a special exception, the copyright owners of the
+dnl macro gives unlimited permission to copy, distribute and modify the
+dnl configure scripts that are the output of Autoconf when processing the
+dnl Macro. You need not follow the terms of the GNU General Public
+dnl License when using or distributing such scripts, even though portions
+dnl of the text of the Macro appear in them. The GNU General Public
+dnl License (GPL) does govern all other use of the material that
+dnl constitutes the Autoconf Macro.
+dnl 
+dnl This special exception to the GPL applies to versions of the
+dnl Autoconf Macro released by this project. When you make and
+dnl distribute a modified version of the Autoconf Macro, you may extend
+dnl this special exception to the GPL to apply to your modified version as
+dnl well.
 
 AC_DEFUN([CC_CHECK_CFLAGS], [
-	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $1"
-	AC_MSG_CHECKING([if compiler supports $1])
-	AC_COMPILE_IFELSE([int a;],
-		[cc_check_cflags=yes],
-		[cc_check_cflags=no])
-	AC_MSG_RESULT([$cc_check_cflags])
-	CFLAGS="$ac_save_CFLAGS"
-	
-	if test "x$cc_check_cflags" = "xyes"; then
-		true
-		$2
-	else
-		true
-		$3
-	fi
+  AC_CACHE_CHECK([if compiler supports $1 flag],
+    AS_TR_SH([cc_cv_cflags_$1]),
+    [ac_save_CFLAGS="$CFLAGS"
+     CFLAGS="$CFLAGS $1"
+     AC_COMPILE_IFELSE([int a;],
+       [eval "AS_TR_SH([cc_cv_cflags_$1])='yes'"],
+       [eval "AS_TR_SH([cc_cv_cflags_$1])="])
+     CFLAGS="$ac_save_CFLAGS"
+    ])
+
+  if eval test [x$]AS_TR_SH([cc_cv_cflags_$1]) = xyes; then
+    ifelse([$2], , [:], [$2])
+  else
+    ifelse([$3], , [:], [$3])
+  fi
 ])
 
+dnl Check for a -Werror flag or equivalent. -Werror is the GCC
+dnl and ICC flag that tells the compiler to treat all the warnings
+dnl as fatal. We usually need this option to make sure that some
+dnl constructs (like attributes) are not simply ignored.
+dnl
+dnl Other compilers don't support -Werror per se, but they support
+dnl an equivalent flag:
+dnl  - Sun Studio compiler supports -errwarn=%all
 AC_DEFUN([CC_CHECK_WERROR], [
-	CC_CHECK_CFLAGS([-Werror], [werror=-Werror])
-
-	dnl This is for SUN Studio compiler
-	if test "x$werror" = "x"; then
-		CC_CHECK_CFLAGS([-errwarn=%all], [werror=-errwarn=%all])
-	fi
+  AC_CACHE_VAL([cc_cv_werror],
+    [CC_CHECK_CFLAGS([-Werror], [cc_cv_werror=-Werror],
+      [CC_CHECK_CFLAGS([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
+    ])
 ])
 
 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((constructor))],
 		[cc_cv_attribute_constructor],
 		[AC_COMPILE_IFELSE([
@@ -55,7 +92,7 @@ AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
 AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((format(printf, n, n)))],
 		[cc_cv_attribute_format],
 		[AC_COMPILE_IFELSE([
@@ -78,7 +115,7 @@ AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
 AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((format_arg(printf)))],
 		[cc_cv_attribute_format_arg],
 		[AC_COMPILE_IFELSE([
@@ -101,7 +138,7 @@ AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
 AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((visibility("...")))],
 		[cc_cv_attribute_visibility],
 		[AC_COMPILE_IFELSE([
@@ -126,7 +163,7 @@ AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
 AC_DEFUN([CC_FLAG_VISIBILITY], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports -fvisibility=hidden],
 		[cc_cv_flag_visibility],
 		[
@@ -151,7 +188,7 @@ AC_DEFUN([CC_FLAG_VISIBILITY], [
 AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((nonnull()))],
 		[cc_cv_attribute_nonnull],
 		[AC_COMPILE_IFELSE([
@@ -175,7 +212,7 @@ AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
 AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((unused))],
 		[cc_cv_attribute_unused],
 		[AC_COMPILE_IFELSE([
@@ -198,7 +235,7 @@ AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
 AC_DEFUN([CC_FUNC_EXPECT], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler has __builtin_expect function],
 		[cc_cv_func_expect],
 		[AC_COMPILE_IFELSE([
@@ -225,7 +262,7 @@ AC_DEFUN([CC_FUNC_EXPECT], [
 AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((sentinel))],
 		[cc_cv_attribute_sentinel],
 		[AC_COMPILE_IFELSE([
@@ -248,7 +285,7 @@ AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
 AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
 	AC_REQUIRE([CC_CHECK_WERROR])
 	ac_save_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $werror"
+	CFLAGS="$CFLAGS $cc_cv_werror"
 	AC_CACHE_CHECK([if compiler supports __attribute__((weak, alias))],
 		[cc_cv_attribute_alias],
 		[AC_COMPILE_IFELSE([