diff --git a/libevent/configure.in b/libevent/configure.in
index bc3eca1..620fd41 100644
--- a/libevent/configure.in
+++ b/libevent/configure.in
@@ -309,6 +309,14 @@ AC_CHECK_TYPES([uint64_t, uint32_t, uint16_t, uint8_t], , ,
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif])
+AC_CHECK_TYPES([fd_mask], , ,
+[#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SELECT_H
+#include <select.h>
+#endif])
+
 AC_CHECK_SIZEOF(long long)
 AC_CHECK_SIZEOF(int)
 AC_CHECK_SIZEOF(short)
diff --git a/libevent/select.c b/libevent/select.c
index ca6639f..af5a879 100644
--- a/libevent/select.c
+++ b/libevent/select.c
@@ -51,6 +51,7 @@
 #endif
 
 #include "event.h"
+#include "evutil.h"
 #include "event-internal.h"
 #include "evsignal.h"
 #include "log.h"
@@ -59,6 +60,12 @@
 #define        howmany(x, y)   (((x)+((y)-1))/(y))
 #endif
 
+#ifndef _EVENT_HAVE_FD_MASK
+#undef NFDBITS
+#define NFDBITS (sizeof(long)*8)
+typedef unsigned long fd_mask;
+#endif
+
 struct selectop {
 	int event_fds;		/* Highest fd in fd set */
 	int event_fdsz;