diff options
1 files changed, 21 insertions, 0 deletions
diff --git a/configure b/configure
index 469b7d29..40712c53 100755
--- a/configure
+++ b/configure
@@ -244,6 +244,27 @@ tryflag CFLAGS_C99FSE -fexcess-precision=standard \
tryflag CFLAGS_C99FSE -frounding-math
+# We may use the may_alias attribute if __GNUC__ is defined, so
+# if the compiler defines __GNUC__ but does not provide it,
+# it must be defined away as part of the CFLAGS.
+printf "checking whether compiler needs attribute((may_alias)) suppression... "
+cat > "$tmpc" <<EOF
+typedef int
+#ifdef __GNUC__
+if $CC $CFLAGS_C99FSE -I./arch/$ARCH -I./include $CPPFLAGS $CFLAGS \
+ -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+printf "no\n"
+printf "yes\n"
+CFLAGS_C99FSE="$CFLAGS_C99FSE -D__may_alias__="
# Check for options that may be needed to prevent the compiler from
# generating self-referential versions of memcpy,, memmove, memcmp,
# and memset. Really, we should add a check to determine if this