runtime: Support sparc64 in lfstack.

R=iant
CC=gofrontend-dev
https://codereview.appspot.com/7221044
libgo: remove exec bit on files

R=iant
CC=gofrontend-dev
https://codereview.appspot.com/7128050

Committer: Ian Lance Taylor <iant@golang.org>
libgo: Add --enable-werror configure option.

R=iant
CC=gofrontend-dev
https://codereview.appspot.com/7225045