build: allow disabling script installation

[matte-schwartz]

Should fix: #1575

actually now that i'm taking a closer look at src/meson.build there's probably a better way to do this change...

[layercak3]

actually now that i'm taking a closer look at src/meson.build there's probably a better way to do this change...

Well, the install script could be replaced with install_subdir('scripts', install_dir : join_paths('share', 'gamescope')) (/usr/share/gamescope is hardcoded so shouldn't use data_dir), but I guess it was done using a shell script so that lua scripts removed fro the repo would be removed in the install prefix, in case someone is installing directly to / instead of cleaning and using a destdir for a distro package? (in this case, we might want to make it so that rm -rf "${DESTDIR}/${MESON_INSTALL_PREFIX}/share/gamescope/scripts" || true is always run regardless of whether the option is set, perhaps by moving it into a separate script, so that scripts are removed in case someone installing directly to / later disabled the option)

[misyltoad]

Yes, it was done in a script to clear out old scripts on install.