bug: package identifier not visible

(should be in the scope chain like any other identifier)

R=r
DELTA=16  (16 added, 0 deleted, 0 changed)
OCL=15884
CL=15884

test/bugs/bug105.go

+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// $G $D/$F.go || echo BUG: should compile
+
+package P
+
+var x int
+
+func f() int {
+	return P.x  // P should be visible
+}
+
+/*
+uetli:~/Source/go1/test/bugs gri$ 6g bug105.go
+bug105.go:8: P: undefined
+bug105.go:9: illegal types for operand: RETURN
+	(<int32>INT32)
+*/