Add -ftrapping-math to default cflags

This makes all tests pass with clang. -ftrapping-math is the default
in gcc but not in clang. pixman-combine-float.c relies on the
-ftrapping-math behaviour.

ok kettenis@

2 files changed, 52 insertions, 0 deletions

diff --git a/lib/pixman/configure b/lib/pixman/configure
index 8d2533b20..2b0cc8308 100644
--- a/lib/pixman/configure
+++ b/lib/pixman/configure
@@ -12593,6 +12593,54 @@ $as_echo "#define USE_OPENMP 1" >>confdefs.h
 fi
 
 
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports -ftrapping-math" >&5
+$as_echo_n "checking whether the compiler supports -ftrapping-math... " >&6; }
+		save_CFLAGS="$CFLAGS"
+	save_LDFLAGS="$LDFLAGS"
+	save_LIBS="$LIBS"
+	CFLAGS=""
+	LDFLAGS=""
+	LIBS=""
+	CFLAGS="$WERROR -ftrapping-math"
+	CFLAGS="$save_CFLAGS $CFLAGS"
+	LDFLAGS="$save_LDFLAGS $LDFLAGS"
+	LIBS="$save_LIBS $LIBS"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+		 int main(int c, char **v) { (void)c; (void)v; return 0; }
+
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  pixman_cc_stderr=`test -f conftest.err && cat conftest.err`
+		 pixman_cc_flag=yes
+else
+  pixman_cc_stderr=`test -f conftest.err && cat conftest.err`
+		 pixman_cc_flag=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+
+	if test "x$pixman_cc_stderr" != "x"; then
+		pixman_cc_flag=no
+	fi
+
+	if test "x$pixman_cc_flag" = "xyes"; then
+		_yesno=yes
+	else
+		_yesno=no
+	fi
+	CFLAGS="$save_CFLAGS"
+	LDFLAGS="$save_LDFLAGS"
+	LIBS="$save_LIBS"
+
+	if test "x$_yesno" = xyes; then
+	   CFLAGS="$CFLAGS -ftrapping-math"
+	fi
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $_yesno" >&5
+$as_echo "$_yesno" >&6; }
+
+
 
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports -fvisibility=hidden" >&5
 $as_echo_n "checking whether the compiler supports -fvisibility=hidden... " >&6; }
diff --git a/lib/pixman/configure.ac b/lib/pixman/configure.ac
index 9a451c5dd..150023c9b 100644
--- a/lib/pixman/configure.ac
+++ b/lib/pixman/configure.ac
@@ -251,6 +251,10 @@ if test "x$ac_cv_prog_c_openmp" != "xunsupported" && test "x$ac_cv_prog_c_openmp
 fi
 AC_SUBST(OPENMP_CFLAGS)
 
+dnl ========================================================================
+dnl make the tests pass with clang
+PIXMAN_CHECK_CFLAG([-ftrapping-math])
+
 dnl =========================================================================
 dnl -fvisibility stuff