add OpenBSD includes

Index: dll/common_includes.h
--- dll/common_includes.h.orig
+++ dll/common_includes.h
@@ -104,7 +104,7 @@ inline void reset_LastError()
     SetLastError(0);
 }
 
-#elif defined(__LINUX__)
+#elif defined(__LINUX__) || defined(__OpenBSD__)
     #include <arpa/inet.h>
 
     #include <sys/types.h>
@@ -118,7 +118,11 @@ inline void reset_LastError()
 
     #include <netinet/in.h>
     #include <netinet/tcp.h>
-    #include <linux/netdevice.h>
+    #if defined(__LINUX__)
+        #include <linux/netdevice.h>
+    #elif defined(__OpenBSD__)
+    	#include <net/if.h>
+    #endif
 
     #include <fcntl.h>
     #include <unistd.h>
@@ -205,4 +209,4 @@ inline std::string ascii_to_lowercase(std::string data
 
 #define LOBBY_CONNECT_APPID ((uint32)-2)
 
-#endif//__INCLUDED_COMMON_INCLUDES__
\ No newline at end of file
+#endif//__INCLUDED_COMMON_INCLUDES__
