Modify libevent to support cygwin - patch will be pushed upstream

This commit was SVN r29387.

opal/mca/event/libevent2021/libevent/event.h

@@ -56,7 +56,7 @@ extern "C" {
 /* For int types. */
 #include <evutil.h>
 
-#ifdef WIN32
+#if defined(WIN32) && !defined(__CYGWIN__)
 #ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN
 #endif

opal/mca/event/libevent2021/libevent/include/event2/util.h

@@ -67,7 +67,7 @@ extern "C" {
 #include <netdb.h>
 #endif
 
-#ifdef WIN32
+#if defined(WIN32) && !defined(__CYGWIN__)
 #include <winsock2.h>
 #else
 #include <sys/socket.h>