define EUNATCH for systems that don't have it

libuv/libuv@6a9e429

Change-Id: Ia09b040844c4e6bb1bd065e9ae0b6c6ea43b7782
Reviewed-on: https://review.couchbase.org/c/libcouchbase/+/195211
Reviewed-by: Jared Casey <jared.casey@couchbase.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>

Author: avsej

plugins/io/libuv/libuv_compat.h

@@ -112,6 +112,9 @@
 #ifndef EFTYPE
 #define EFTYPE EAI_FAIL
 #endif
+#ifndef EUNATCH
+#define EUNATCH EAI_FAIL
+#endif
 
 #define OK 0