PR middle-end/97631 - bogus "writing one too many bytes" warning for memcpy with...

PR middle-end/97631 - bogus "writing one too many bytes" warning for memcpy with strlen argument

gcc/ChangeLog:

	PR middle-end/97631
	* tree-ssa-strlen.c (maybe_warn_overflow): Test rawmem.
	(handle_builtin_stxncpy_strncat): Rename locals.  Determine
	destination size from allocation calls.  Issue a more appropriate
	kind of warning.
	(handle_builtin_memcpy): Pass true as rawmem to maybe_warn_overflow.
	(handle_builtin_memset): Same.

gcc/testsuite/ChangeLog:

	PR middle-end/97631
	* c-c++-common/Wstringop-overflow.c: Remove unexpected warnings.
	Add an xfail.
	* c-c++-common/Wstringop-truncation.c: Add expected warnings.
	* gcc.dg/Wstringop-overflow-10.c: Also enable -Wstringop-truncation.
	* gcc.dg/Wstringop-overflow-66.c: New test.
	* gcc.dg/tree-ssa/strncpy-2.c: Adjust expected warning.