nonblocking: fix mingw test failures

Actually testing on mingw uncovered a few more problems.

* lib/nonblocking.c (set_nonblocking_flag): Succeed when clearing
non-blocking flag on regular file.
(get_nonblocking_flag): Set errno on invalid fd.
* tests/test-nonblocking.c (main): Avoid test failure on
directories if fchdir is not active.
* modules/nonblocking-tests (Depends-on): Drop unused dependency.

Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/tests/test-nonblocking.c b/tests/test-nonblocking.c
index 0762cd0ae1..f1b7610543 100644
--- a/tests/test-nonblocking.c
+++ b/tests/test-nonblocking.c
@@ -55,11 +55,14 @@ main (void)
 
   /* Test directories; setting nonblocking is unspecified.  */
   fd_file = open (".", O_RDONLY);
-  ASSERT (STDERR_FILENO < fd_file);
-  ASSERT (get_nonblocking_flag (fd_file) == 0);
-  ASSERT (set_nonblocking_flag (fd_file, false) == 0);
-  ASSERT (get_nonblocking_flag (fd_file) == 0);
-  ASSERT (close (fd_file) == 0);
+  if (STDERR_FILENO < fd_file)
+    {
+      /* mingw can't open directories unless fchdir module is active.  */
+      ASSERT (get_nonblocking_flag (fd_file) == 0);
+      ASSERT (set_nonblocking_flag (fd_file, false) == 0);
+      ASSERT (get_nonblocking_flag (fd_file) == 0);
+      ASSERT (close (fd_file) == 0);
+    }
 
   /* Test pipes.  */
   ASSERT (pipe (fd_pipe) == 0);