Revert "Disable __longjmp_chk protection"

This reverts commit b73a3693.

This version of the check doesn't work with generic-gnu, and figuring
out the correct symbol version at configure time is probably more work
than this is worth. May revisit in the future.

Change-Id: I6c75e88bd3bd82a4b21e09a25780fe53aacb7d70

vpx/internal/vpx_codec_internal.h

@@ -45,7 +45,6 @@
 #define VPX_CODEC_INTERNAL_H
 #include "../vpx_decoder.h"
 #include "../vpx_encoder.h"
-#include "vpx_config.h"
 #include <stdarg.h>
 
 
@@ -436,23 +435,6 @@ vpx_codec_pkt_list_get(struct vpx_codec_pkt_list *list,
 
 #include <stdio.h>
 #include <setjmp.h>
-
-/* GLIBC started intercepting calls to longjmp in version 2.11, if the
- * FORTIFY_SOURCE flag is defined (it's defined by default on Ubuntu).
- * This can cause problems running under older versions of GLIBC (ie,
- * for binary distributions), so work around it by linking to the
- * underlying longjmp call directly.
- */
-#if defined(__GNUC_PREREQ)
-#if __GNUC_PREREQ (2,11)
-#if ARCH_X86_64
-__asm__(".symver __longjmp_chk,longjmp@GLIBC_2.2.5");
-#else
-__asm__(".symver __longjmp_chk,longjmp@GLIBC_2.0");
-#endif
-#endif
-#endif
-
 struct vpx_internal_error_info
 {
     vpx_codec_err_t  error_code;