Configure gcc to emit .note.GNU-stack for both 32 and 64 bits PowerPC.

Mark gcc-provided asm files as not requiring executable stack.

It seems that non-FreeBSD ABIs for powerpc64 claim stack non-executable.
Due to this, rs6000_elf_end_indicate_exec_stack() only emit the note for
32 bit target. I decided not to change FreeBSD ABI and patch
emit the notes for both variants.

Reviewed and tested by:	nwhitehorn

contrib/gcc/config/rs6000/crtsavres.asm

@@ -305,3 +305,5 @@ FUNC_END(_restgpr_15_x)
 FUNC_END(_restgpr_14_x)
 
 #endif
+
+	.section .note.GNU-stack,"",%progbits

contrib/gcc/config/rs6000/freebsd.h

@@ -230,6 +230,8 @@
       }
 #endif
 
+#define TARGET_ASM_FILE_END rs6000_elf_end_indicate_exec_stack
+
 /* FreeBSD doesn't support saving and restoring 64-bit regs with a 32-bit
    kernel. This is supported when running on a 64-bit kernel with
    COMPAT_FREEBSD32, but tell GCC it isn't so that our 32-bit binaries
@@ -242,3 +244,5 @@
 #define PROFILE_HOOK(LABEL) \
   do { if (TARGET_64BIT) output_profile_hook (LABEL); } while (0)
 
+#undef NEED_INDICATE_EXEC_STACK
+#define NEED_INDICATE_EXEC_STACK 1

contrib/gcc/config/rs6000/rs6000.c

@@ -18426,7 +18426,7 @@ rs6000_elf_declare_function_name (FILE *file, const char *name, tree decl)
 static void
 rs6000_elf_end_indicate_exec_stack (void)
 {
-  if (TARGET_32BIT)
+  if (NEED_INDICATE_EXEC_STACK)
     file_end_indicate_exec_stack ();
 }
 #endif

contrib/gcc/config/rs6000/tramp.asm

@@ -115,3 +115,5 @@ FUNC_START(__trampoline_setup)
 FUNC_END(__trampoline_setup)
 
 #endif
+
+	.section .note.GNU-stack,"",%progbits