Properly detect timeout in pthread_mutex_lock_timeout_np_impl

Previously we were checking against a positive errno which
would not be returned from a system call.

Change-Id: I8e3a36f6fbf5ccc2191a152a1def37e2d6f93124
Small style cleanup.

Change-Id: Ib45a4a2296232968296f9bd7cc3592ba46fd412d

Conflicts:
	libc/bionic/pthread_cond.cpp
Clean up more recursive FORTIFY_SOURCE calls

Don't use FORTIFY_SOURCE on functions which implement
FORTIFY_SOURCE, to avoid infinite recursion problems.

The previous patch only addressed one of the problems.

Bug: 12216860
Change-Id: I6f30ae7cb5b481be9942add18182ea4839d348a6
We actually have modfl.

Change-Id: I22bb4d14f99a418819f2941c2dfec49094807c5f

Conflicts:
	libm/fake_long_double.c