$NetBSD$

Support *BSD.

--- ddio/CMakeLists.txt.orig	2024-08-24 18:38:47.867589860 +0000
+++ ddio/CMakeLists.txt
@@ -16,7 +16,7 @@ set(CPPS
   lnxkey_null.cpp
   lnxmouse.cpp
   lnxkey_sdl.cpp
-  $<$<PLATFORM_ID:Darwin,Linux>:
+  $<$<PLATFORM_ID:Darwin,Linux,FreeBSD,NetBSD,OpenBSD>:
     lnxfile.cpp
   >
   $<$<PLATFORM_ID:Windows>: