Add support for Cgywin, apparently it is enough just to open the tty again in

the server and fd passing is not necessary. Needs some ifdefs unfortunately but
no way around that and some of them can go next time we're willing to do a
protocol bump. Patch from J Raynor jxraynor at gmail dot com.

compat.h

@@ -30,6 +30,10 @@
 #define __packed __attribute__ ((__packed__))
 #endif
 
+#ifndef ECHOPRT
+#define ECHOPRT 0
+#endif
+
 #ifndef HAVE_BSD_TYPES
 typedef uint8_t u_int8_t;
 typedef uint16_t u_int16_t;
@@ -210,6 +214,7 @@ int	 	 daemon(int, int);
 
 #ifndef HAVE_B64_NTOP
 /* b64_ntop.c */
+#undef b64_ntop /* for Cygwin */
 int		 b64_ntop(const char *, size_t, char *, size_t);
 #endif