Workaround for borked sem_init library function.

Workaround for borked sem_init library function.

This adds a workaround that zeroes out semaphores before they are
initialized. Some versions of sem_init (e.g. GLIBC_2.0) fail to fully
zero out the semaphore, leading to {errno == ENOSYS} with subsequent
sem_timedwait calls.

R=machenbach@chromium.org
BUG=chromium:536813
LOG=n

Committed: https://crrev.com/263340113713db788e56abda61062dd9513b9f79
Cr-Commit-Position: refs/heads/master@{#31232}

[Michael Achenbach, 2015-10-13 09:38:25]

lgtm

[Michael Starzinger, 2015-10-13 09:45:40]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-10-13 09:45:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1407463002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1407463002/20001

[commit-bot: I haz the power, 2015-10-13 09:53:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-13 09:53:19]

Patchset 2 (id:??) landed as
https://crrev.com/263340113713db788e56abda61062dd9513b9f79
Cr-Commit-Position: refs/heads/master@{#31232}