recycle G structs

R=r
DELTA=1  (1 added, 0 deleted, 0 changed)
OCL=33887
CL=33904
diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 4735685..bd8e954 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -433,6 +433,7 @@
 				gp->lockedm = nil;
 				m->lockedg = nil;
 			}
+			gfput(gp);
 			if(--sched.gcount == 0)
 				exit(0);
 			break;