code review 125620044: cmd/yacc: remove Makefile and build expr using go generate

cmd/yacc: remove Makefile and build expr using go generate
It now serves as an example for go generate as well as for yacc.

NOTE: Depends on go generate, which is not yet checked in.
This is a proof of concept of the approach.
That is http://codereview.appspot.com/125580044.

[r, 2014-08-20 20:13:25]

Hello rsc (cc: golang-codereviews@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go

[rsc, 2014-08-23 22:56:39]

LGTM

https://codereview.appspot.com/125620044/diff/1/src/cmd/yacc/expr/expr.y
File src/cmd/yacc/expr/expr.y (left):

https://codereview.appspot.com/125620044/diff/1/src/cmd/yacc/expr/expr.y#oldc...
src/cmd/yacc/expr/expr.y:14: // This tag will be copied to the generated file to
prevent that file
Nice to see this go away.

[r, 2014-08-24 18:34:49]

*** Submitted as https://code.google.com/p/go/source/detail?r=68b84694821c ***

cmd/yacc: remove Makefile and build expr using go generate
It now serves as an example for go generate as well as for yacc.

NOTE: Depends on go generate, which is not yet checked in.
This is a proof of concept of the approach.
That is http://codereview.appspot.com/125580044.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://codereview.appspot.com/125620044