[tlbuild] Broken shebangs in TeX Live scripts

[Andreas Scherer]

FYI,

 > and macOS might not have bash at all
At least up to version 11.6.5 (Big Sur on Mac Mini M1 as of 2020, but 
most likely also Monterey), macOS uses "GNU bash 3.2.57(1)" as "/bin/sh" 
(maybe with the "--posix" option?). ;o)

As of macOS Catalina (that was 10.15, right?), the log-in shell 
(terminal) has switched from bash to zsh. This can be changed in the 
system preferences (users & groups); the "/bin/sh" can be reset via 
"/var/select/sh".

Note that K/Ubuntu 20.04 has "bash 5.0.17(1)" (current version seems to 
be 5.1.16) as log-in shell and "dash 0.5.10.2" as "/bin/sh".

Take care,
Andreas