spawn-pipe tests: Avoid test failure on native Windows

[Bruno Haible]

On mingw, I see a test failure of test-spawn-pipe.sh. This patch fixes it.


2018-10-04  Bruno Haible  <address@hidden>

        spawn-pipe tests: Avoid test failure on native Windows.
        * tests/test-spawn-pipe-child.c (main): On native Windows, don't expect
        that fd 2 is closed.

diff --git a/tests/test-spawn-pipe-child.c b/tests/test-spawn-pipe-child.c
index 14522f5..b5fd7cb 100644
--- a/tests/test-spawn-pipe-child.c
+++ b/tests/test-spawn-pipe-child.c
@@ -98,9 +98,9 @@ main (int argc, char *argv[])
     case 1:
       /* Expect fd 2 is closed.
          But on HP-UX 11, fd 2 gets automatically re-opened to /dev/null if it
-         was closed. Future POSIX will allow this, see
-         <http://austingroupbugs.net/view.php?id=173>.  */
-#if !defined __hpux
+         was closed.  Similarly on native Windows.  Future POSIX will allow
+         this, see <http://austingroupbugs.net/view.php?id=173>.  */
+#if !(defined __hpux || (defined _WIN32 && ! defined __CYGWIN__))
       ASSERT (! is_open (STDERR_FILENO));
 #endif
       break;