Replace the CFLAGS-checking code with a common macro from xine-lib.

Instead of writing custom code to check for cflags checking, import a
copy of attributes.m4 from xine-lib's repository and use the
CC_CHECK_CFLAGS macro.

The advantage lies not only in being able to reduce the custom code in
configure.ac, but also in the fact that the CC_CHECK_CFLAGS macro
caches the results, making ./configure -C quite faster on second run.

Check for the CFLAGS for any compiler and not just GCC, if the
compiler does support the flag it is better to u se it anyway,
otherwise it will be skipped.

1 files changed, 6 insertions, 24 deletions

diff --git a/configure.ac b/configure.ac
index a7fbd1a1..f56be997 100644
--- a/configure.ac
+++ b/configure.ac
@@ -98,30 +98,12 @@ if test "x$M4" = xno ; then
    AC_MSG_ERROR([m4 missing])
 fi
 
-# GCC flags
-
-test_gcc_flag() {
-    AC_LANG_CONFTEST([int main(int argc, char*argv[]) {}])
-    $CC -c conftest.c $CFLAGS -o conftest.o > /dev/null 2> /dev/null
-    ret=$?
-    rm -f conftest.o
-    return $ret
-}
-
-# If using GCC specify some additional parameters
-if test "x$GCC" = "xyes" ; then
-    DESIRED_FLAGS="-Wall -W -Wextra -pedantic -pipe -Wformat -Wold-style-definition -Wdeclaration-after-statement -Wfloat-equal -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wshadow -Wendif-labels -Wpointer-arith -Wcast-align -Wwrite-strings -Winline -Wno-unused-parameter -ffast-math"
-
-    for flag in $DESIRED_FLAGS ; do
-        AC_MSG_CHECKING([whether $CC accepts $flag])
-        if test_gcc_flag $flag ; then
-           CFLAGS="$CFLAGS $flag"
-           AC_MSG_RESULT([yes])
-        else
-           AC_MSG_RESULT([no])
-        fi
-    done
-fi
+dnl Compiler flags
+DESIRED_FLAGS="-Wall -W -Wextra -pedantic -pipe -Wformat -Wold-style-definition -Wdeclaration-after-statement -Wfloat-equal -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wshadow -Wendif-labels -Wpointer-arith -Wcast-align -Wwrite-strings -Winline -Wno-unused-parameter -ffast-math"
+
+for flag in $DESIRED_FLAGS ; do
+  CC_CHECK_CFLAGS([$flag], [CFLAGS="$CFLAGS $flag"])
+done
 
 # Native atomic operation support
 AC_ARG_ENABLE([atomic-arm-linux-helpers],