virsh: fix mingw startup

* .gnulib: Update to latest, for pipe2.
* bootstrap.conf (gnulib_modules): Add pipe2.
* src/util/event_poll.c (virEventPollInit): Use it, to avoid
problematic virSetCloseExec on mingw.

bootstrap.conf

@@ -54,6 +54,7 @@ nonblocking
 perror
 physmem
 pipe-posix
+pipe2
 poll
 posix-shell
 pthread

src/util/event_poll.c

@@ -29,6 +29,7 @@
 #include <sys/time.h>
 #include <errno.h>
 #include <unistd.h>
+#include <fcntl.h>
 
 #include "threads.h"
 #include "logging.h"
@@ -657,11 +658,7 @@ int virEventPollInit(void)
         return -1;
     }
 
-    if (pipe(eventLoop.wakeupfd) < 0 ||
-        virSetNonBlock(eventLoop.wakeupfd[0]) < 0 ||
-        virSetNonBlock(eventLoop.wakeupfd[1]) < 0 ||
-        virSetCloseExec(eventLoop.wakeupfd[0]) < 0 ||
-        virSetCloseExec(eventLoop.wakeupfd[1]) < 0) {
+    if (pipe2(eventLoop.wakeupfd, O_CLOEXEC | O_NONBLOCK) < 0) {
         virReportSystemError(errno, "%s",
                              _("Unable to setup wakeup pipe"));
         return -1;