This reverts the upstream patch.

Warn if user requests __FORTIFY_SOURCE but it is disabled
author	Roland Mc Grath <roland@hack.frob.com>	
Tue, 8 May 2012 17:44:57 +0000 (19:44 +0200)
committer	Andreas Jaeger <jaegerandi@gmail.com>	
Tue, 8 May 2012 17:44:57 +0000 (19:44 +0200)
commit	05c2c9618f583ea4acd69b3fe5ae2a2922dd2ddc
tree	cf5cd345bf757fd5296ff7e0b8dcd7f142fc3d37
parent	4b30f61a1ea78de9b0e84a54fc6ee96ea70e6ed5

The reason to revert it is that some packages that use
autoconf to detect system headers, the warning will give the
wrong result.

--- include/features.h	2016-06-01 16:26:04.534295058 -0700
+++ include/features.h	2016-06-01 16:27:48.485859977 -0700
@@ -326,18 +326,14 @@
 # define __USE_REENTRANT	1
 #endif
 
-#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
-# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
-#  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
-# elif !__GNUC_PREREQ (4, 1)
-#  warning _FORTIFY_SOURCE requires GCC 4.1 or later
-# 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
-#endif
-#ifndef __USE_FORTIFY_LEVEL
+#else
 # define __USE_FORTIFY_LEVEL 0
 #endif