* calls.c (special_function_p): New argument fork_or_exec.
	(expand_call): When profile_arc_flag is set and the function
	is in the fork_or_exec group, call __bb_fork_func first.
	* libgcc2.c, _bb module (__bb_fork_func): New function.
	(__bb_exit_func): If fcntl F_SETLKW is available, use it to lock
	output file.
	* config/svr4.h (TARGET_HAS_F_SETLKW): Define.
	* tree.h (special_function_p): Update prototype.

From-SVN: r31636