cmd/vet: use default compiler when determining type sizes

    
    Fixes a segfault running vet on alpha.
    
    Patch by Uros Bizjak.
    
    Reviewed-on: https://go-review.googlesource.com/c/152437

From-SVN: r266781

gcc/go/gofrontend/MERGE

-9e016dfe198152f870005ac844fe22c02e5349e3
+7259d9a403db2784c7d03239c6a50e730062fc61
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/cmd/vet/types.go

@@ -310,4 +310,4 @@ func (f *File) matchStructArgType(t printfArgType, typ *types.Struct, arg ast.Ex
 	return true
 }
 
-var archSizes = types.SizesFor("gc", build.Default.GOARCH)
+var archSizes = types.SizesFor(build.Default.Compiler, build.Default.GOARCH)