TeXLive installer fails to run certain postinstall scripts

[Karl Berry]

    After some debug, I found that the issue comes from this recent
    change:
    https://github.com/TeX-Live/installer/commit/ff98be775bf48aa576cbc25aa337dd5626af6550

Please report config.guess bugs to config-patches at gnu.org (there is no
other address, so have to use -patches even if you don't have a patch).
I don't have access to a musl machine, so I can't guess what might be
needed.

All TL does, regarding musl, is look for the string in the config.guess
output. --thanks, karl.