c++: support target attr for DECL_LOCAL_DECL_P fns [PR99108]

c++: support target attr for DECL_LOCAL_DECL_P fns [PR99108]

We crash when target attribute get_function_versions_dispatcher is called
for a function that is not registered in call graph.  This was happening
because we were calling it for the function-local decls that aren't in the
symbol table, instead of the corresponding namespace-scope decls that are.

gcc/cp/ChangeLog:

	PR c++/99108
	* call.c (get_function_version_dispatcher): Handle
	DECL_LOCAL_DECL_P.
	* decl.c (maybe_version_functions): Likewise.
	(maybe_mark_function_versioned): New.
	* name-lookup.c (push_local_extern_decl_alias): No longer static.
	* name-lookup.h (push_local_extern_decl_alias): Adjust.

gcc/testsuite/ChangeLog:

	PR c++/99108
	* g++.target/i386/pr99108.C: New test.

Co-authored-by: Jason Merrill <jason@redhat.com>