New comment by Duncaen on void-packages repository

https://github.com/void-linux/void-packages/pull/38494#issuecomment-1207458649

Comment:
The extra complexity isn't that big, I expect this change to reduce the number of lines, at the moment its like +11 lines.

Its basically just creating a per distfile target list of indexes into the `distfiles` and `checksum` variables and then tries to download each distfile target by looping through the per target indexes until a download is successful.
The looping already exists for `XBPS_DISTFILES_MIRROR` and the current implementation kinda already works by indexing into distfiles+checksums but in a weird way, which is why the rewrite will be more compact/simpler, by just using indexed arrays.