gc: fix import name resolution

Fixes #403.

R=ken2
https://golang.org/cl/180052
diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index 6d86a6a..35e7742 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -195,7 +195,7 @@
 		}
 		my->def = pack;
 		my->lastlineno = $1;
-		import->block = 1;	// at top level
+		my->block = 1;	// at top level
 	}
 
 
diff --git a/test/fixedbugs/bug233.go b/test/fixedbugs/bug233.go
new file mode 100644
index 0000000..31bb673
--- /dev/null
+++ b/test/fixedbugs/bug233.go
@@ -0,0 +1,10 @@
+// $G $D/$F.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.
+
+package main
+import p "fmt"
+var _ = p.Print
+var fmt = 10