configure.ac: allow several compiler flags for clang
The flac configury marked clang as 'not being gcc' and excluded
a lot of compiler switches, most importantly the visibility flags,
from being used with it. This was done possibly after a problem
reported at: https://github.com/erikd/libsndfile/issues/49 .
This patch does the following:
- m4/gcc_version.m4 (XIPH_GCC_VERSION): set GCC_MAJOR_VERSION and
GCC_MINOR_VERSION to 0 for non-gcc. Previously, they were left
unset.
- configure: the gcc version checks are, naturally, against non-
zero values, so, allow many compiler switches to be used with
clang without affecting real-gcc cases.
- configure: When setting CFLAGS="-O3 -funroll-loops", also set
CXXFLAGS="-O3". Prevents g++ warnings with _FORTIFY_SOURCE, i.e.:
'_FORTIFY_SOURCE requires compiling with optimization (-O)'
Tested compilation using gcc-7.3.1 and clang-5.0.2 on x86_64-linux,
and gcc-4.4.7 and clang-3.4.2 on an i686-linux. Also tested cross-
compiling for Mac OS X using clang-5.0.2.
diff --git a/configure.ac b/configure.ac
index 6efefaf..88f89a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -429,11 +429,12 @@
dnl are provided, we can set defaults to our liking
AS_IF([test "x${ax_enable_debug}" = "xno" && test "x${enable_flags_setting}" = "xyes"], [
CFLAGS="-O3 -funroll-loops"
+ CXXFLAGS="-O3"
])
-XIPH_GCC_VERSION
+XIPH_GCC_VERSION dnl Sets a non-zero GCC_XXX_VERSION for gcc, not clang. checks below rely on that..
-if test x$ac_cv_c_compiler_gnu = xyes ; then
+if test x$ac_cv_c_compiler_gnu = xyes -o x$xiph_cv_c_compiler_clang = xyes ; then
CFLAGS="$CFLAGS -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Waggregate-return -Wcast-align -Wnested-externs -Wshadow -Wundef -Wmissing-declarations -Winline " # -Wcast-qual -Wbad-function-cast -Wwrite-strings -Wconversion
CXXFLAGS="$CXXFLAGS -Wall -Wextra -Wcast-align -Wshadow -Wwrite-strings -Wctor-dtor-privacy -Wnon-virtual-dtor -Wreorder -Wsign-promo -Wundef " # -Wcast-qual -Wbad-function-cast -Wwrite-strings -Woverloaded-virtual -Wmissing-declarations
@@ -448,13 +449,22 @@
XIPH_ADD_CXXFLAGS([-Weffc++])
AC_LANG_POP([C++])
- if test "$GCC_MAJOR_VERSION" -ge 4 && test "$OBJ_FORMAT" = elf; then
+ if test x$xiph_cv_c_compiler_clang = xyes -a "$OBJ_FORMAT" = elf; then
+ CPPFLAGS="$CPPFLAGS -DFLAC__USE_VISIBILITY_ATTR"
+ CFLAGS="$CFLAGS -fvisibility=hidden"
+ CXXFLAGS="$CXXFLAGS -fvisibility=hidden"
+ elif test "$GCC_MAJOR_VERSION" -ge 4 && test "$OBJ_FORMAT" = elf; then
CPPFLAGS="$CPPFLAGS -DFLAC__USE_VISIBILITY_ATTR"
CFLAGS="$CFLAGS -fvisibility=hidden"
CXXFLAGS="$CXXFLAGS -fvisibility=hidden"
fi
- if test "$GCC_MAJOR_VERSION" -ge 4 && test "$OBJ_FORMAT" = macho; then
+
+ if test x$xiph_cv_c_compiler_clang = xyes -a "$OBJ_FORMAT" = macho; then
+ CPPFLAGS="$CPPFLAGS -DFLAC__USE_VISIBILITY_ATTR"
+ CFLAGS="$CFLAGS -fvisibility=hidden"
+ CXXFLAGS="$CXXFLAGS -fvisibility=hidden"
+ elif test "$GCC_MAJOR_VERSION" -ge 4 && test "$OBJ_FORMAT" = macho; then
CPPFLAGS="$CPPFLAGS -DFLAC__USE_VISIBILITY_ATTR"
CFLAGS="$CFLAGS -fvisibility=hidden"
CXXFLAGS="$CXXFLAGS -fvisibility=hidden"