Undertale Linux Fixups

Undertale is built with an old version of Game Maker that requires manually downloading older libraries and pointing the game to it.

Copy the lib dir into the game dir within the installed Undertale directory.

Add this line to start.sh so use the manually downloaded libraries:

export LD_LIBRARY_PATH=./lib:$LD_LIBRARY_PATH

Because of amdgpu graphics driver, replace the default runner line with this:

R600_DEBUG=check_vm ./runner

(a fixed-up start.sh is included in this dir)