# define __USE_REENTRANT 1
#endif
-#if _FORTIFY_SOURCE > 0 && __GNUC_PREREQ (4, 1) && __OPTIMIZE__ > 0
-# if _FORTIFY_SOURCE == 1
-# define __USE_FORTIFY_LEVEL 1
-# elif _FORTIFY_SOURCE > 1
+#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0 \
+ && __GNUC_PREREQ (4, 1) && defined __OPTIMIZE__ && __OPTIMIZE__ > 0
+# if _FORTIFY_SOURCE > 1
# define __USE_FORTIFY_LEVEL 2
+# else
+# define __USE_FORTIFY_LEVEL 1
# endif
+#else
+# define __USE_FORTIFY_LEVEL 0
#endif
/* We do support the IEC 559 math functionality, real and complex. */