[Ada] Do not attempt to re-arm guard page on x86_64-vx7(r2)

[Pierre-Marie de Rodat]

A change in the API prohibits accessing Tcb fields directly. The bug in
VxWorks7 (failure to re-arm the guard page) now appears to be fixed, so
this is no long necessary.

Tested on x86_64-pc-linux-gnu, committed on trunk

2019-07-10  Doug Rupp  <r...@adacore.com>

gcc/ada/

        * init.c: Do not attempt to re-arm guard page on x86_64-vx7(r2).
--- gcc/ada/init.c
+++ gcc/ada/init.c
@@ -1725,7 +1725,7 @@ __gnat_install_handler (void)
 #include <iv.h>
 #endif
 
-#if ((defined (ARMEL) && (_WRS_VXWORKS_MAJOR == 6)) || defined (__x86_64__)) && !defined(__RTP__)
+#if ((defined (ARMEL) && (_WRS_VXWORKS_MAJOR == 6))) && !defined(__RTP__)
 #define VXWORKS_FORCE_GUARD_PAGE 1
 #include <vmLib.h>
 extern size_t vxIntStackOverflowSize;