Unix user directory name hard-coded

[coderjo]

In ArchHooks_Unix.cpp, the user data directory name is hardcoded. Is there a reason it isn't deriving from PRODUCT_ID, like the other OSes?

On the current 5_1-new, it is "stepmania-5.1", but on master (which some people seem to be using), it is still "stepmania-5.0" rather than 5.2.

[shakesoda]

oversight from when it was just "stepmania"

another issue is that we should be checking env for XDG_DATA_HOME (typically ~/.local/share), possibly also XDG_CONFIG_HOME (typically ~/.config) and using that value as the base directory for save data, and not just home dir. ~/.stepmania should be last resort if we can't use xdg dirs

the right thing to do, technically, would be to write preferences into xdg_config_home, but in practice we've always gotten complaints about splitting this kind of stuff up, so i'd rather leave things in xdg_data_home

[coderjo]

If we move to using the XDG spec, the Cache directory should use XDG_CACHE_HOME