re PR gcov-profile/49484 (gcov crash if two(or more) forks happen at the same time)

2012-03-12  Richard Guenther  <rguenther@suse.de>

	* gthr.h (__GTHREAD_MUTEX_INIT_FUNCTION): Adjust specification.
	* gthr-posix.h (__GTHREAD_MUTEX_INIT_FUNCTION): Define.
	(__gthread_mutex_init_function): New function.
	* gthr-single.h (__GTHREAD_MUTEX_INIT_FUNCTION): Define.

	PR gcov/49484
	* libgcov.c: Include gthr.h.
	(__gcov_flush_mx): New global variable.
	(init_mx, init_mx_once): New functions.
	(__gcov_flush): Protect self with a mutex.
	(__gcov_fork): Re-initialize mutex after forking.
	* unwind-dw2-fde.c: Change condition under which to use
	__GTHREAD_MUTEX_INIT_FUNCTION.

From-SVN: r185231