Recognize gccgo error messages.

bug039.go:6:7: error: redefinition of 'x'
bug039.go:5:1: note: previous definition of 'x' was here

bug049.go:6:9: error: incompatible types in binary expression

bug062.go:6:7: error: incompatible type in initialization

bug086.go:5:1: error: control reaches end of non-void function

bug103.go:8:2: error: variable has no type

bug121.go:9:2: error: expected signature or type name

bug131.go:7:7: error: incompatible type in initialization

bug165.go:10:8: error: expected complete type

bug171.go:5:1: error: control reaches end of non-void function
bug171.go:6:1: error: control reaches end of non-void function

bug172.go:7:6: error: expected integer type

bug182.go:7:2: error: if statement expects boolean expression

bug183.go:10:5: error: incompatible types in assignment
bug183.go:19:5: error: incompatible types in assignment

R=rsc
DELTA=15  (0 added, 0 deleted, 15 changed)
OCL=33168
CL=33175

test/fixedbugs/bug172.go

@@ -8,5 +8,5 @@ package main
 
 func f() {
 	a := true;
-	a |= a;	// ERROR "illegal.*OR|bool"
+	a |= a;	// ERROR "illegal.*OR|bool|expected"
 }