[dev.garbage] code review 169120043: cmd/gc, runtime: add locks around print statements

cmd/gc, runtime: add locks around print statements

Now each C printf, Go print, or Go println is guaranteed
not to be interleaved with other calls of those functions.
This should help when debugging concurrent failures.

[rsc, 2014-11-05 19:24:48]

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

I'd like you to review this change to the dev.garbage branch of
https://code.google.com/p/go/

[rlh, 2014-11-05 19:29:10]

LGTM

[rsc, 2014-11-05 19:42:59]

*** Submitted as https://code.google.com/p/go/source/detail?r=7bcd3f25a2a3 ***

[dev.garbage] cmd/gc, runtime: add locks around print statements

Now each C printf, Go print, or Go println is guaranteed
not to be interleaved with other calls of those functions.
This should help when debugging concurrent failures.

LGTM=rlh
R=rlh
CC=golang-codereviews
https://codereview.appspot.com/169120043

[gobot, 2014-11-08 01:30:41]

This CL appears to have broken the linux-arm-luitvd builder.
See http://build.golang.org/log/3eb9177bced505ab10d72b7acc017b718031b12b