[tlbuild] wget in TL now needs https

[Karl Berry]

Mojca, like all of us, I am just struggling to do the best we can to
support as many people as we can.

I don't think it's appropriate to ask CTAN to expend their time
maintaining a separate list of http mirrors purely for TL download
purposes on systems that don't have an lwp or wget or curl that supports
ssl. Feel free to ask them yourself if you wish.

I have no problem with leaving any or all of our TL wget binaries that
only support http in place so that, as you say, users can explicitly
give an http (or ftp for that matter) mirror.

We could pass --no-check-certificates when calling our tl-provided wget
to avoid maintaining a cert database (which would be untenable). I am
somewhat surprised that we do not already do that.

tlmgr tries (system) LWP first, then (system) curl, before (either
system or tl) wget. Although it may test for the presence of all of
them, that's the order in which they'll actually be used, as far as I
know.

Users can always specify their own programs, their own arguments, and/or
adjust preferences using the envvars TEXLIVE_DOWNLOAD,
TL_DOWNLOAD_PROGRAM, TL_DOWNLOAD_ARGS, TEXLIVE_PREFER_OWN.

https://tug.org/texlive/doc/tlmgr.html#ENVIRONMENT-VARIABLES
(or http :) --best, karl.