* fcntl.cc (fcntl_worker): Remove static storage class.

* flock.cc (flock): Use struct __flock64. Call fcntl_worker.
	Use Cygwin errno functions instead of accessing errno directly.
	* winsup.h: Declare fcntl_worker.

winsup/cygwin/fcntl.cc

@@ -19,7 +19,7 @@ details. */
 #include "cygheap.h"
 #include "thread.h"
 
-static int
+int
 fcntl_worker (int fd, int cmd, void *arg)
 {
   int res;