From d4a1b345dd16591ff6f17c67ee519afebe2f9792 Mon Sep 17 00:00:00 2001

From: sezero <sezero@users.sourceforge.net>

Date: Tue, 8 Oct 2019 20:25:55 +0300

Subject: [PATCH] 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.

---

configure.ac | 18 ++++++++++++++----

m4/gcc_version.m4 | 3 +++

2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac

index 6efefaf..88f89a9 100644

--- a/configure.ac

+++ b/configure.ac

@@ -429,11 +429,12 @@ dnl If debugging is disabled AND no CFLAGS/CXXFLAGS/CPPFLAGS/LDFLAGS

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 @@ if test x$ac_cv_c_compiler_gnu = xyes ; then

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"

diff --git a/m4/gcc_version.m4 b/m4/gcc_version.m4

index 1c53086..e6aaa60 100644

--- a/m4/gcc_version.m4

+++ b/m4/gcc_version.m4

@@ -22,6 +22,9 @@ if test "x$ac_cv_c_compiler_gnu" = "xyes" ; then

GCC_MAJOR_VERSION=`echo $GCC_VERSION | cut -d. -f 1`

GCC_MINOR_VERSION=`echo $GCC_VERSION | cut -d. -f 2`

+else

+ GCC_MAJOR_VERSION=0

+ GCC_MINOR_VERSION=0

fi

AC_SUBST(GCC_VERSION)

--

1.7.1