Add new snprintf/vsnprintf implementation. This should fix the compability

problems between Win32 (with its broken implementation) and the standard
stdio API.  Also fixed a bug in debug output where long messages got
truncated to 1023 chars, and in xmpp_stanza_to_text where long stanzas
got truncated by one character.

src/common.h

@@ -277,4 +277,8 @@ void disconnect_mem_error(xmpp_conn_t * const conn);
 /* auth functions */
 void auth_handle_open(xmpp_conn_t * const conn);
 
+/* replacement snprintf and vsnprintf */
+int xmpp_snprintf (char *str, size_t count, const char *fmt, ...);
+int xmpp_vsnprintf (char *str, size_t count, const char *fmt, va_list arg);
+
 #endif /* __LIBSTROPHE_COMMON_H__ */