* crypt/Makefile (libcrypt-routines): Add sha256-crypt, sha256,

* crypt/Makefile (libcrypt-routines): Add sha256-crypt, sha256,

	sha512-crypt, and sha512.
	(tests): Add sha256test, sha256c-test, sha512test, and sha512c-test.
	(distribute): Add sha256.h and sha512.h.
	* crypt/crypt-entry.c (crypt): Recognize the new $5$ and $6$ prefixes
	and call the appropriate code.
	* crypt/sha256-crypt.c: New file.
	* crypt/sha256.c: New file.
	* crypt/sha256.h: New file.
	* crypt/sha256c-test.c: New file.
	* crypt/sha256test.c: New file.
	* crypt/sha512-crypt.c: New file.
	* crypt/sha512.c: New file.
	* crypt/sha512.h: New file.
	* crypt/sha512c-test.c: New file.
	* crypt/sha512test.c: New file.

	* sysdeps/unix/sysv/linux/sparc/sparc32/clone.S (__thread_start):
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/clone.S (__thread_start):
	Likewise.