adding possibility to implement own debug function

UDPTCPNetwork.h

@@ -79,7 +79,9 @@ void debug_set_logfile (std::string fname);
 void _debug (char *srcfile, int srcline, char *srcfunc, char *fmt,...);
 void _errorexit (char *srcfile, int srcline, char *srcfunc, char *fmt,...);
 
+#ifndef debug
 #define debug(...) _debug ((char*)__FILE__, __LINE__, (char*)__FUNCTION__, (char*)__VA_ARGS__)
+#endif
 #define errorexit(...) _errorexit ((char*)__FILE__, __LINE__, (char*)__FUNCTION__, (char*)__VA_ARGS__)
 
 #endif