$NetBSD$

Support *BSD.

--- ddebug/CMakeLists.txt.orig	2024-08-24 18:38:21.358398028 +0000
+++ ddebug/CMakeLists.txt
@@ -4,7 +4,7 @@ set(HEADERS
   mono.h)
 set(CPPS
   debug.cpp
-  $<$<PLATFORM_ID:Darwin,Linux>:
+  $<$<PLATFORM_ID:Darwin,Linux,FreeBSD,NetBSD,OpenBSD>:
     lnxdebug.cpp
     lnxmono.cpp
   >