BUGFIX: Fix compilation on systems with EPOLLRDHUP undefined.

Since epolltable-internal.h uses this define, it must be defined before that is included.

epoll.c

@@ -59,6 +59,14 @@
 #include "evmap-internal.h"
 #include "changelist-internal.h"
 #include "time-internal.h"
+
+/* Since Linux 2.6.17, epoll is able to report about peer half-closed connection
+   using special EPOLLRDHUP flag on a read event.
+*/
+#if !defined(EPOLLRDHUP)
+#define EPOLLRDHUP 0
+#endif
+
 #include "epolltable-internal.h"
 
 #if defined(EVENT__HAVE_SYS_TIMERFD_H) &&			  \
@@ -72,13 +80,6 @@
 #define USING_TIMERFD
 #endif
 
-/* Since Linux 2.6.17, epoll is able to report about peer half-closed connection
-   using special EPOLLRDHUP flag on a read event.
-*/
-#if !defined(EPOLLRDHUP)
-#define EPOLLRDHUP 0
-#endif
-
 struct epollop {
 	struct epoll_event *events;
 	int nevents;