Restore our local change to remove GNU_STACK program header:

http://cvsweb.netbsd.org/bsdweb.cgi/src/external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c#rev1.13

Index: external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c
===================================================================
RCS file: /home/netbsd/src/external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c,v
retrieving revision 1.24
diff -p -u -r1.24 rs6000.c
--- external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c	12 Apr 2021 07:23:06 -0000	1.24
+++ external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c	13 Apr 2021 02:35:57 -0000
@@ -20282,7 +20284,7 @@ rs6000_elf_file_end (void)
 		 aix_struct_return ? 2 : 1);
     }
 #endif
-#if defined (POWERPC_LINUX) || defined (POWERPC_FREEBSD) || defined(POWERPC_NETBSD)
+#if defined (POWERPC_LINUX) || defined (POWERPC_FREEBSD)
   if (TARGET_32BIT || DEFAULT_ABI == ABI_ELFv2)
     file_end_indicate_exec_stack ();
 #endif