diff -Naur odamex-src-0.5.6/odalpapi/net_io.cpp odamex-src-0.5.6.patched/odalpapi/net_io.cpp
--- odamex-src-0.5.6/odalpapi/net_io.cpp	2011-11-04 23:59:42.000000000 -0400
+++ odamex-src-0.5.6.patched/odalpapi/net_io.cpp	2012-09-20 02:19:30.000000000 -0400
@@ -27,6 +27,7 @@
 #include <iostream>
 #include <sstream>
 #include <cstdio>
+#include <unistd.h>
 #include <cstdlib>
 #include <cstring>
 #include <cstdarg>