<signal.h> shouldn't get you the contents of <errno.h>, and <fcntl.h>
shouldn't get you the contents of <unistd.h>.
Change-Id: I347499cd8671bfee98e6b8e875a97cab3a3655d3
bionic_systrace.h contains an implementation of tracing that
can be used with systrace.py and its associated viewer. pthread_mutex
now uses this tracing to track pthread_mutex contention, which can be
enabled by using the "bionic" command line option to systrace.
Bug: 15116468
Change-Id: I30ed5b377c91ca4c36568a0e647ddf95d4e4a61a
