Dxx-rebirth - Descent I/II game data & add-ons

[sleve_mcdichael]

dxx-rebirth.sh attempts to download Descent II demo/shareware data even if registered version files already exist (it only checks if the demo itself is present or not; D1 uses the same filename for shareware/registered versions so issue is self-correcting in that case):

if [[ ! -f "$dest_d2/D2DEMO.HOG" ]]; then
    downloadAndExtract "$D2X_SHARE_URL" "$dest_d2"

Solution: simply expand the test parameters to check for both versions:

if [[ ! -f "$dest_d2/D2DEMO.HOG" && ! -f "$dest_d2/DESCENT2.HOG" ]]; then

Further, I say "attempts to" because the shareware and add-on file targets are no longer available hosted at dxx-rebirth.com:

local D1X_SHARE_URL='https://www.dxx-rebirth.com/download/dxx/content/descent-pc-shareware.zip'
local D2X_SHARE_URL='https://www.dxx-rebirth.com/download/dxx/content/descent2-pc-demo.zip'
local D1X_HIGH_TEXTURE_URL='https://www.dxx-rebirth.com/download/dxx/res/d1xr-hires.dxa'
local D1X_OGG_URL='https://www.dxx-rebirth.com/download/dxx/res/d1xr-sc55-music.dxa'
local D2X_OGG_URL='https://www.dxx-rebirth.com/download/dxx/res/d2xr-sc55-music.dxa'

https://github.com/dxx-rebirth/dxx-rebirth/issues/747

At present they may still be downloaded via the wayback machine but I don't think that's a good permanent solution to source them from, going forward. Would the answer be for RP to self-hosting these like done for doom and duke3d sharewares?

    local D1X_SHARE_URL="$__archive_url/descent-pc-shareware.zip"
    #etc.

PR additionally ignores case when detecting user-provided game files, so shareware datas are not downloaded whether user provides old DOS files in ALL CAPS or modern Steam files in lowercase (similar to protocultor@0b107d45):

https://github.com/RetroPie/RetroPie-Setup/pull/3922