[dev.cc] cmd/new5a etc, cmd/internal/asm: edit to produce working Go code

These assemblers produce byte-for-byte identical output
to the ones written in C.

They are primarily a proof that cmd/internal/obj can be used
standalone to produce working object files. (The use via objwriter
starts by deserializing an already-constructed internal representation,
so objwriter does not exercise the code in cmd/internal/obj that
creates such a representation from scratch.)

Change-Id: I1793d8d010046cfb9d8b4d2d4469e7f47a3d3ac7
Reviewed-on: https://go-review.googlesource.com/3143
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/.gitignore b/.gitignore
index f1c7263..585cd0f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,14 +26,12 @@
 misc/cgo/stdio/run.out
 misc/cgo/testso/main
 misc/dashboard/builder/builder
-src/cmd/?a/y.output
 src/liblink/anames?.c
-src/cmd/cc/y.output
+src/cmd/*/y.output
 src/cmd/cgo/zdefaultcc.go
 src/cmd/dist/dist.dSYM
 src/cmd/gc/mkbuiltin1
 src/cmd/gc/opnames.h
-src/cmd/gc/y.output
 src/cmd/go/zdefaultcc.go
 src/cmd/internal/obj/zbootstrap.go
 src/go/doc/headscan