runtime: fix darwin build

Add place holder for runtime.osyield.

R=golang-dev
CC=golang-dev
https://golang.org/cl/5149049

diff --git a/src/pkg/runtime/darwin/thread.c b/src/pkg/runtime/darwin/thread.c
index c5d8ba4d3e6621c1bec025cfa2652d03552f9070..b35dae02fe2fd7560e3363aa5e4c615f41f8e33a 100644 (file)
--- a/src/pkg/runtime/darwin/thread.c
+++ b/src/pkg/runtime/darwin/thread.c
@@ -496,3 +496,9 @@ runtime·sigpanic(void)
        }
        runtime·panicstring(runtime·sigtab[g->sig].name);
 }
+
+// TODO(rsc): place holder to fix build.
+void
+runtime·osyield(void)
+{
+}