Ifdef out network code for M&P

M&P contains network code despite M&P not being a Steam/GOG release (as
Steam/GOG releases are full releases of the game, not
custom-levels-only releases).

While unlocking achievements is already ifdef'd out in M&P, let's remove
the network code entirely to make sure people can't do other shenanigans
with M&P builds, and also to have a smaller binary size.

desktop_version/src/Network.c

@@ -1,7 +1,18 @@
 #include <stdint.h>
 
+#include "MakeAndPlay.h"
+
 #define UNUSED(expr) (void)(expr)
 
+#ifdef MAKEANDPLAY
+	#ifdef STEAM_NETWORK
+		#undef STEAM_NETWORK
+	#endif
+	#ifdef GOG_NETWORK
+		#undef GOG_NETWORK
+	#endif
+#endif
+
 #ifdef STEAM_NETWORK
 #define STEAM_NUM 1
 #else