* c-common.h (c_language_kind): New type.
(c_language): New variab.e
* c-common.c (lang_get_alias_set): Don't put structures in
non-zero alias sets in C++.
* c-decl.c (c_language): Define it.
* c-lex.c (doing_objc_thang): Remove.
* c-tree.h (doing_objc_thang): Make it a macro.
* objc/objc-act.c (lang_decode_option): Set c_language, not
doing_objc_thang.