This quiets all.bash noise for upcoming features we know about.
The all.bash warnings will now only print for things not in next.txt
(or in next.txt but not in the API).
Once an API is frozen, we rename next.txt to a new frozen file
(like go1.txt)
Fixes#3651
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6218069
Unbalanced extra right parenthesis produced an internal error instead of
a more descriptive one.
Fixes#3406.
R=r, rsc
CC=golang-dev
https://golang.org/cl/6201063
Adds new file api/go1.txt, locking down the current API.
Any changes to the API will need to update that file.
run.bash (but not make.bash, or Windows) will check for
accidental API changes.
R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/5820070
