Match gccgo error messages.
Match gccgo error messages.

convlit.go:17: error: incompatible type in initialization
convlit.go:18: error: incompatible types in binary expression
convlit.go:19: error: incompatible types in binary expression
convlit.go:20: error: incompatible types in binary expression
convlit.go:21: error: incompatible types in binary expression
convlit.go:23: error: cannot convert non-integer constant
convlit.go:24: error: integer type overflow
convlit.go:25: error: floating point overflow

R=rsc
DELTA=5  (0 added, 0 deleted, 5 changed)
OCL=17649
CL=17661
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go