gcc6: Upgrade to 6.4

(From OE-Core rev: 02d2a14333b3cbc8e6acf74245f3db6b6b94c91b)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
(cherry picked from commit 7874fa86cb583fe6a178b95ead09430486197197)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/gcc/gcc-6.4/0008-missing-execinfo_h.patch

@@ -0,0 +1,28 @@
+From 6dde3da24ef4b9b357bca670d8551cab3fdda843 Mon Sep 17 00:00:00 2001
+From: Khem Raj <raj.khem@gmail.com>
+Date: Fri, 29 Mar 2013 08:48:10 +0400
+Subject: [PATCH 08/46] missing-execinfo_h
+
+Signed-off-by: Khem Raj <raj.khem@gmail.com>
+
+Upstream-Status: Pending
+---
+ boehm-gc/include/gc.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/boehm-gc/include/gc.h b/boehm-gc/include/gc.h
+index 6b38f2d..fca98ff 100644
+--- a/boehm-gc/include/gc.h
++++ b/boehm-gc/include/gc.h
+@@ -503,7 +503,7 @@ GC_API GC_PTR GC_malloc_atomic_ignore_off_page GC_PROTO((size_t lb));
+ #if defined(__linux__) || defined(__GLIBC__)
+ # include <features.h>
+ # if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \
+-     && !defined(__ia64__)
++     && !defined(__ia64__) && !defined(__UCLIBC__)
+ #   ifndef GC_HAVE_BUILTIN_BACKTRACE
+ #     define GC_HAVE_BUILTIN_BACKTRACE
+ #   endif
+-- 
+2.8.2
+