add pthread_cancel, obtained from OpenBSD.

eischen (Daniel Eischen) added wrappers to protect against cancled
threads orphaning internal resources.

the cancelability code is still a bit fuzzy but works for test
programs of my own, OpenBSD's and some examples from ORA's books.

add readdir_r to both libc and libc_r

add some 'const' attributes to function parameters

Reviewed by: eischen, jasone

1 files changed, 2 insertions, 0 deletions

diff --git a/lib/libc_r/uthread/uthread_wait4.c b/lib/libc_r/uthread/uthread_wait4.c
index fc6cfba..baa697c 100644
--- a/lib/libc_r/uthread/uthread_wait4.c
+++ b/lib/libc_r/uthread/uthread_wait4.c
@@ -42,6 +42,7 @@ wait4(pid_t pid, int *istat, int options, struct rusage * rusage)
 {
 	pid_t           ret;
 
+	_thread_enter_cancellation_point();
 	_thread_kern_sig_defer();
 
 	/* Perform a non-blocking wait4 syscall: */
@@ -61,6 +62,7 @@ wait4(pid_t pid, int *istat, int options, struct rusage * rusage)
 	}
 
 	_thread_kern_sig_undefer();
+	_thread_leave_cancellation_point();
 
 	return (ret);
 }