lockfile: wait using sleep_millisec() instead of select()

Use the new function sleep_millisec() to delay execution for a short
time. This avoids the invocation of select() with just a timeout, but
no file descriptors. Such a use of select() is quit with EINVAL on
Windows, leading to no delay at all.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

lockfile.c

@@ -157,14 +157,6 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 	return lk->fd;
 }
 
-static int sleep_microseconds(long us)
-{
-	struct timeval tv;
-	tv.tv_sec = 0;
-	tv.tv_usec = us;
-	return select(0, NULL, NULL, NULL, &tv);
-}
-
 /*
  * Constants defining the gaps between attempts to lock a file. The
  * first backoff period is approximately INITIAL_BACKOFF_MS
@@ -214,7 +206,7 @@ static int lock_file_timeout(struct lock_file *lk, const char *path,
 		backoff_ms = multiplier * INITIAL_BACKOFF_MS;
 		/* back off for between 0.75*backoff_ms and 1.25*backoff_ms */
 		wait_ms = (750 + rand() % 500) * backoff_ms / 1000;
-		sleep_microseconds(wait_ms*1000);
+		sleep_millisec(wait_ms);
 		remaining_ms -= wait_ms;
 
 		/* Recursion: (n+1)^2 = n^2 + 2n + 1 */