Recognize gccgo error messages:
Recognize gccgo error messages:

interface5.go:15:5: error: incompatible types in assignment
interface5.go:16:5: error: incompatible types in assignment

(Yes, these could be better).

R=rsc
DELTA=2  (0 added, 0 deleted, 2 changed)
OCL=22821
CL=22826
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go