Fix typo in __GNUC_PREREQ__ version check (#1086)

__GNUC_MINOR__ was missing a trailing underscore, which prevented
__builtin_expect() from being used via __predict_false() in the error
path of checked functions like __memcpy_chk(). __builtin_expect is
defined from GCC 3 (2001) and Clang 2.2 (2008).

Signed-off-by: Tiago de Paula <tiagodepalves@gmail.com>

Author: marmitar

common/inc/tlibc/sys/cdefs.h

@@ -57,7 +57,7 @@
 /*
  * Macro to test if we're using a specific version of gcc or later.
  */
-#if defined __GNUC__ && defined __GNUC_MINOR_
+#if defined __GNUC__ && defined __GNUC_MINOR__
 # define __GNUC_PREREQ__(ma, mi) \
     ((__GNUC__ > (ma)) || (__GNUC__ == (ma) && __GNUC_MINOR__ >= (mi)))
 #else