gcc/

	PR target/64056
	* doc/sourcebuild.texi: Add mempcpy and stpcpy for Effective-Target Keywords.

gcc/testsuite/

	PR target/64056
	* lib/target-supports.exp (check_effective_target_stpcpy): New.
	* gcc.target/i386/chkp-strlen-2.c: Add stpcpy target check.

From-SVN: r218415