Fixes uclibc build as uclibc does not include backtrace functionality

Patch sent upstream:
http://lists.freedesktop.org/archives/mesa-dev/2014-October/069506.html

Bugtracker: https://bugs.freedesktop.org/show_bug.cgi?id=85197

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>

diff -uNr Mesa-10.3.1.org/configure.ac Mesa-10.3.1/configure.ac
--- Mesa-10.3.1.org/configure.ac	2014-10-12 22:42:38.000000000 +0200
+++ Mesa-10.3.1/configure.ac	2014-10-19 19:15:11.000000000 +0200
@@ -539,6 +539,9 @@
 dnl See if posix_memalign is available
 AC_CHECK_FUNC([posix_memalign], [DEFINES="$DEFINES -DHAVE_POSIX_MEMALIGN"])
 
+dnl Check for backtrace support
+AC_CHECK_HEADER([execinfo.h], [DEFINES="$DEFINES -DHAVE_EXECINFO_H"])
+
 dnl Check for pthreads
 case "$host_os" in
 mingw*)
diff -uNr Mesa-10.3.1.org/src/mapi/glapi/gen/gl_gentable.py Mesa-10.3.1/src/mapi/glapi/gen/gl_gentable.py
--- Mesa-10.3.1.org/src/mapi/glapi/gen/gl_gentable.py	2014-10-12 22:42:39.000000000 +0200
+++ Mesa-10.3.1/src/mapi/glapi/gen/gl_gentable.py	2014-10-19 19:21:32.913846414 +0200
@@ -42,7 +42,7 @@
 #endif
 
 #if (defined(GLXEXT) && defined(HAVE_BACKTRACE)) \\
-	|| (!defined(GLXEXT) && defined(DEBUG) && !defined(_WIN32_WCE) && !defined(__CYGWIN__) && !defined(__MINGW32__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__))
+	|| (!defined(GLXEXT) && defined(DEBUG) && defined(HAVE_EXECINFO_H) && !defined(_WIN32_WCE) && !defined(__CYGWIN__) && !defined(__MINGW32__) && !defined(__OpenBSD__) && !defined(__NetBSD__) && !defined(__DragonFly__))
 #define USE_BACKTRACE
 #endif
 
diff -uNr Mesa-10.3.1.org/src/mesa/drivers/dri/i915/intel_regions.c Mesa-10.3.1/src/mesa/drivers/dri/i915/intel_regions.c
--- Mesa-10.3.1.org/src/mesa/drivers/dri/i915/intel_regions.c	2014-05-06 00:45:23.000000000 +0200
+++ Mesa-10.3.1/src/mesa/drivers/dri/i915/intel_regions.c	2014-10-19 19:23:13.833850693 +0200
@@ -65,7 +65,9 @@
 #define _DBG(...) {debug_backtrace(); DBG(__VA_ARGS__);}
 
 /* Backtracing debug support */
+#ifdef HAVE_EXECINFO_H
 #include <execinfo.h>
+#endif
 
 static void
 debug_backtrace(void)