gc: diagnose init loop involving func

Fixes #2295.

R=ken2
CC=golang-dev
https://golang.org/cl/5655057

src/cmd/gc/sinit.c

@@ -65,7 +65,7 @@ init1(Node *n, NodeList **out)
 		if(nerrors > 0)
 			errorexit();
 
-		print("initialization loop:\n");
+		print("%L: initialization loop:\n", n->lineno);
 		for(l=initlist;; l=l->next) {
 			if(l->next == nil)
 				break;
@@ -106,7 +106,7 @@ init1(Node *n, NodeList **out)
 			break;
 		*/
 			if(1) {
-				init1(n->defn->right, out);
+				init2(n->defn->right, out);
 				if(debug['j'])
 					print("%S\n", n->sym);
 				if(!staticinit(n, out)) {

test/fixedbugs/bug413.go

+// errchk $G $D/$F.go
+
+// Copyright 2012 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 p
+
+func f(i int) int { return i }
+
+var i = func() int {a := f(i); return a}()  // ERROR "initialization loop"
\ No newline at end of file