[PATCH v6 3/4] poll() exits too early with EFAULT if 1st arg is NULL

If poll() is used as a milli-second sleep, like in help.c, by passing a NULL
in the 1st and a 0 in the 2nd arg, it exits with EFAULT.

As per Paolo Bonzini, the original author, this is a bug and to be fixed 
like
in this commit, which is not to exit if the 2nd arg is 0. It got fixed in
gnulib in the same manner the other day.

Signed-off-by: Joachim Schmitz <redacted>
---
 compat/poll/poll.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compat/poll/poll.c b/compat/win32/poll.c
index 403eaa7..9e7a25c 100644
--- a/compat/poll/poll.c
+++ b/compat/poll/poll.c

@@ -349,7 +349,7 @@ poll (struct pollfd *pfd, nfds_t nfd, int timeout)

   /* EFAULT is not necessary to implement, but let's do it in the
      simplest case. */
-  if (!pfd)
+  if (!pfd && nfd)
     {
       errno = EFAULT;
       return -1;

-- 
1.7.12