Fix build on non-linux systems. The HOST_NAME_MAX is not portable,

POSIX way to find it out is to use sysconf(_SC_HOST_NAME_MAX),
but for now just fix it with ifndef.

dprint.c

@@ -25,7 +25,6 @@
  * \brief OpenSIPS Debug console print functions
  */
 
-
 #include "dprint.h"
 #include "log_interface.h"
 #include "globals.h"
@@ -35,6 +34,10 @@
 #include <stdio.h>
 #include <strings.h>
 
+#if !defined(HOST_NAME_MAX)
+#define HOST_NAME_MAX 255
+#endif
+
 /* used internally by the log interface */
 typedef void (*log_print_pre_fmt_f)(log_print_f gen_print_func, int log_level,
 	int facility, char *module, const char *func,