-CC_CHECK_FLAGS_APPEND([with_cppflags], [CPPFLAGS], [\
- -Wp,-D_FORTIFY_SOURCE=2])
+AS_CASE([$CFLAGS], [*-O[[12345\ ]]*], [
+ CC_CHECK_FLAGS_APPEND([with_cppflags], [CPPFLAGS], [\
+ -Wp,-D_FORTIFY_SOURCE=2])], [
+ AC_MSG_RESULT([skipping -D_FORTIFY_SOURCE, optimization not enabled])])