ww: separate package identity from declared name

cmd/w6c/gc.h

@@ -38,6 +38,8 @@ struct Cg {
 				 * lib/foo binds to `foo.frob` regardless
 				 * of which other modules also export `frob`.
 				 * Set by cgfn before walking the body. */
+	int	cur_source;	/* lexical source-file scope of the current
+				 * declaration; selects its own import bindings. */
 	int	framesize;	/* bytes of locals; 16-byte aligned */
 	int	curoff;		/* current top of locals */
 	Scope	*locals;	/* (name → offset) tracked via Sym */