osprocid can be -1

src/libthread/threadimpl.h

diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
index cb5b016..f0b55d9 100644
--- a/src/libthread/threadimpl.h
+++ b/src/libthread/threadimpl.h
@@ -95,7 +95,7 @@
 #ifdef PLAN9PORT_USING_PTHREADS
 	pthread_t	osprocid;
 #else
-	uint		osprocid;
+	int		osprocid;
 #endif
 	Lock		lock;
 	int			nswitch;