* cppinit.c (BC): New macro.
	(builtin_array): Add __GXX_WEAK__.
	* cpplib.h (builtin_type): Add BT_WEAK.
	* cppmacro.c (builtin_macro): Handle BT_WEAK.
	* defaults.h (SUPPORTS_ONE_ONLY): Define.
	* varasm.c (SUPPORTS_ONE_ONLY): Do not define.

From-SVN: r39436