diff --git a/configure b/configure index 469b7d29..40712c53 100755 --- a/configure +++ b/configure @@ -243,6 +243,27 @@ tryflag CFLAGS_C99FSE -fexcess-precision=standard \ || { test "$ARCH" = i386 && tryflag CFLAGS_C99FSE -ffloat-store ; } tryflag CFLAGS_C99FSE -frounding-math +# +# We may use the may_alias attribute if __GNUC__ is defined, so +# if the compiler defines __GNUC__ but does not provide it, +# it must be defined away as part of the CFLAGS. +# +printf "checking whether compiler needs attribute((may_alias)) suppression... " +cat > "$tmpc" </dev/null 2>&1 ; then +printf "no\n" +else +printf "yes\n" +CFLAGS_C99FSE="$CFLAGS_C99FSE -D__may_alias__=" +fi + # # Check for options that may be needed to prevent the compiler from # generating self-referential versions of memcpy,, memmove, memcmp,