Recognize gccgo error message.

const2.go:7:9: error: expected '='

Uses '.' to recognize the quotation marks, as the actual
characters printed depend on the user's locale.

R=rsc
DELTA=1  (0 added, 0 deleted, 1 changed)
OCL=26360
CL=26373
diff --git a/test/const2.go b/test/const2.go
index b3b10de..2ff71ee 100644
--- a/test/const2.go
+++ b/test/const2.go
@@ -8,5 +8,5 @@
 
 const (
 	A int = 1;
-	B byte;	// ERROR "type without expr"
+	B byte;	// ERROR "type without expr|expected .=."
 )