games/dxx-rebirth: Fix build with scons 4.5.0+
PR: 274524
Reference: https://pkg-status.freebsd.org/pb2/data/124i386-default-foo/2023-11-02_15h08m17s/logs/errors/dxx-rebirth-20220929_2.log
Obtained from: https://github.com/dxx-rebirth/dxx-rebirth/commit/189ac23f61605903eb3eaa0004d287b7bd9296bc
https://github.com/dxx-rebirth/dxx-rebirth/commit/769164a55bd74f2f11d14dd5175fbee01cf77638