Match gccgo error messages.

bug197.go:10:5: error: incompatible type in initialization
bug197.go:11:5: error: incompatible type in initialization
bug197.go:12:5: error: incompatible type in initialization
bug197.go:13:5: error: incompatible type in initialization
bug197.go:20:13: error: incompatible types in binary expression
bug197.go:21:27: error: incompatible types in binary expression

R=rsc
DELTA=6  (0 added, 0 deleted, 6 changed)
OCL=34135
CL=34177

test/fixedbugs/bug197.go

@@ -11,18 +11,18 @@ type U int
 
 var x int
 
-var t T = int(0)	// ERROR "cannot use"
-var t1 T = int(x)	// ERROR "cannot use"
-var u U = int(0)	// ERROR "cannot use"
-var u1 U = int(x)	// ERROR "cannot use"
+var t T = int(0)	// ERROR "cannot use|incompatible"
+var t1 T = int(x)	// ERROR "cannot use|incompatible"
+var u U = int(0)	// ERROR "cannot use|incompatible"
+var u1 U = int(x)	// ERROR "cannot use|incompatible"
 
 type S string
 var s S
 
 var s1 = s + "hello"
 var s2 = "hello" + s
-var s3 = s + string("hello")	// ERROR "invalid operation"
-var s4 = string("hello") + s	// ERROR "invalid operation"
+var s3 = s + string("hello")	// ERROR "invalid operation|incompatible"
+var s4 = string("hello") + s	// ERROR "invalid operation|incompatible"
 
 var r string