Move checks for pollfd.fd and nfds_t.

Move the checks for struct pollfd.fd and nfds_t to before the sandboxing
checks.  This groups all the sandbox checks together so we can skip them
all when sandboxing is disabled.

configure.ac

@@ -3537,6 +3537,26 @@ AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 )
 fi
 
+AC_CHECK_MEMBERS([struct pollfd.fd], [], [], [[
+#include <sys/types.h>
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#ifdef HAVE_SYS_POLL_H
+#include <sys/poll.h>
+#endif
+]])
+
+AC_CHECK_TYPES([nfds_t], , , [
+#include <sys/types.h>
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#ifdef HAVE_SYS_POLL_H
+#include <sys/poll.h>
+#endif
+])
+
 # Decide which sandbox style to use
 sandbox_arg=""
 AC_ARG_WITH([sandbox],
@@ -3614,26 +3634,6 @@ else
     )
 fi
 
-AC_CHECK_MEMBERS([struct pollfd.fd], [], [], [[
-#include <sys/types.h>
-#ifdef HAVE_POLL_H
-#include <poll.h>
-#endif
-#ifdef HAVE_SYS_POLL_H
-#include <sys/poll.h>
-#endif
-]])
-
-AC_CHECK_TYPES([nfds_t], , , [
-#include <sys/types.h>
-#ifdef HAVE_POLL_H
-#include <poll.h>
-#endif
-#ifdef HAVE_SYS_POLL_H
-#include <sys/poll.h>
-#endif
-])
-
 AC_MSG_CHECKING([if setrlimit(RLIMIT_NOFILE,{0,0}) works])
 AC_RUN_IFELSE(
 	[AC_LANG_PROGRAM([[