cmd/compile/internal/gc: eliminate bstdout

Just use Ctxt.Bso instead.

Change-Id: I68f1639f0b4c238ae5499ef49e78a5d734417979
Reviewed-on: https://go-review.googlesource.com/29114
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/go.go

@@ -5,7 +5,6 @@
 package gc
 
 import (
-	"bufio"
 	"cmd/compile/internal/ssa"
 	"cmd/internal/bio"
 	"cmd/internal/obj"
@@ -285,8 +284,6 @@ var Ctxt *obj.Link
 
 var writearchive bool
 
-var bstdout *bufio.Writer
-
 var Nacl bool
 
 var continpc *obj.Prog

src/cmd/compile/internal/gc/main.go

@@ -107,8 +107,7 @@ func Main() {
 
 	Ctxt = obj.Linknew(Thearch.LinkArch)
 	Ctxt.DiagFunc = Yyerror
-	bstdout = bufio.NewWriter(os.Stdout)
-	Ctxt.Bso = bstdout
+	Ctxt.Bso = bufio.NewWriter(os.Stdout)
 
 	localpkg = mkpkg("")
 	localpkg.Prefix = "\"\""

src/cmd/compile/internal/gc/subr.go

@@ -59,7 +59,7 @@ func (x byLineno) Less(i, j int) bool { return x[i].lineno < x[j].lineno }
 func (x byLineno) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
 
 func Flusherrors() {
-	bstdout.Flush()
+	Ctxt.Bso.Flush()
 	if len(errors) == 0 {
 		return
 	}