c++: -Wshadow=compatible-local type vs var [PR100608]

c++: -Wshadow=compatible-local type vs var [PR100608]

The patch for PR92024 changed -Wshadow=compatible-local to warn if either
new or old decl was a type, but the rationale only talked about the case
where both are types.  If only one is, they aren't compatible.

	PR c++/100608

gcc/cp/ChangeLog:

	* name-lookup.c (check_local_shadow): Use -Wshadow=local
	if exactly one of 'old' and 'decl' is a type.

gcc/testsuite/ChangeLog:

	* g++.dg/warn/Wshadow-compatible-local-3.C: New test.