add os.ForkExec, os.Exec, os.Wait, exec.OpenCmd.

as thread-safe as possible, given the surrounding system.
add stub RWLock implementation.

R=r
DELTA=852  (834 added, 6 deleted, 12 changed)
OCL=25046
CL=25053

1 files changed, 17 insertions, 0 deletions

diff --git a/src/lib/sync/mutex.go b/src/lib/sync/mutex.go
index 1269027e11..8e05cd819d 100644
--- a/src/lib/sync/mutex.go
+++ b/src/lib/sync/mutex.go
@@ -39,3 +39,20 @@ func (m *Mutex) Unlock() {
 	semrelease(&m.sema);
 }
 
+// Stub implementation of r/w locks.
+// This satisfies the semantics but
+// is not terribly efficient.
+// TODO(rsc): Real r/w locks.
+
+type RWMutex struct {
+	Mutex;
+}
+
+func (m *RWMutex) RLock() {
+	m.Lock();
+}
+
+func (m *RWMutex) RUnlock() {
+	m.Unlock();
+}
+