Get builtins tests ready for linker plugin.

Get builtins tests ready for linker plugin.

	* gcc.c-torture/execute/builtins/memcpy-chk.c (s2,s3,l1): Mark volatile.
	* gcc.c-torture/execute/builtins/memops-asm-lib.c (my_memcpy, my_bcopy, my_memset,
	my_bzero): Mark used.
	* gcc.c-torture/execute/builtins/memset-chk.c (l1, l3): Mark volatile.
	* gcc.c-torture/execute/builtins/memmove-chk.c (s1,s2,s3,l1): Mark volatile.
	* gcc.c-torture/execute/builtins/mempcpy-chk.c (s2,s3,l1): Mark volatile

From-SVN: r168588