re PR c++/30112 (pragma redefine_extname fails when namespaces are involved)

re PR c++/30112 (pragma redefine_extname fails when namespaces are involved)

	PR c++/30112
gcc/c-family/
	* c-common.h: Declare c_linkage_bindings.
	* c-pragma.c (handle_pragma_redefine_extname): Use it.
gcc/
	* c-decl.c (c_linkage_bindings): Define.
gcc/cp/
	* decl.c (cp_finish_decl): Apply pragma redefine_extname in
	other namespaces as well.
	* name-lookup.c (c_linkage_bindings): Define.
	(lookup_extern_c_fun_in_all_ns): Rename from
	lookup_extern_c_fun_binding_in_all_ns.  Return tree.
	(pushdecl_maybe_friend_1): Adjust.  Copy DECL_ASSEMBLER_NAME.

Co-Authored-By: Mark Glisse <marc.glisse@normalesup.org>
From-SVN: r176650