Remove gcc/files/patch-libcpp which has not been present on lang/gcc49

and lang/gcc48, but is something we have in lang/gcc47 and that lang/gcc
carried over from the days it was about GCC 4.7 (so surviving both the
transitions to GCC 4.8 and recently GCC 4.9).

The underlying issue was addressed upstream 2014-10-24 with r216679,
and in FreeBSD head 2013-09-06 by theraven@ who fixed fixed our
iconv.h to not include stdbool.h.

PR:		161417

lang/gcc/files/patch-libcpp

@@ -1,11 +0,0 @@
---- UTC
---- libcpp/internal.h	2012-07-30 09:24:59.000000000 +0000
-+++ libcpp/internal.h	2013-09-04 00:41:26.000000000 +0000
-@@ -27,6 +27,7 @@
- #include "cpp-id-data.h"
- 
- #if HAVE_ICONV
-+#define __bool_true_false_are_defined
- #include <iconv.h>
- #else
- #define HAVE_ICONV 0