[tlbuild] request for modest enhancement of tlmgr

[Nelson H. F. Beebe]

This morning, I successfully followed the recipe at

	http://www.math.utah.edu/pub/texlive-utah/#install

to install a new TeX Live 2020 tree on DragonFlyBSD.  However,
I found two infelicities:

(1) the installer does not find any binaries for this system
    (expected, but I have them at the above Web site), so it quits
    with

	./install-tl: No binary platform specified/available, quitting.
   
    Could we please consider changing that to do something like this
    instead:

	./install-tl: No binary platform specified/available, proceeding with fingers crossed
	You may be able to find binaries for your system at 
	http://www.math.utah.edu/pub/texlive-utah/

     I worked around that problem for now by installing an
     arbitrarily-chosen platform binary directory that I then deleted
     after the installation.

(2) After the installation, I attempted to run

	tlmgr update --self
	tlmgr update --all

    However, that bails out with

	Use of uninitialized value $OS in string eq at \
		/usr/uumath/texlive/2020/tlpkg/TeXLive/TLUtils.pm line 321.
	Use of uninitialized value $OS in string eq at \
		/usr/uumath/texlive/2020/tlpkg/TeXLive/TLUtils.pm line 329.

    Inspection of the referenced TLUtils.pm file at those line
    locations show that they follow this code snippet:

	my @OSs = qw(aix cygwin darwin freebsd hpux irix
		     kfreebsd linux netbsd openbsd solaris);
	for my $os (@OSs) {
	  # Match word boundary at the beginning of the os name so that
	  #   freebsd and kfreebsd are distinguished.
	  # Do not match word boundary at the end of the os so that
	  #   solaris2 is matched.
	  $OS = $os if $guessed_platform =~ /\b$os/;
	}

    The tlpkg/installer/config.guess script reports

	x86_64-unknown-dragonfly5.7

    on this system, but its mangling to derive an OS value does not
    reduce to any of the 11 names in the @OSs list.

    Can tlmgr please be tweaked to support DragonFlyBSD?

    I run that O/S on several VMs, plus a deskside physical machine,
    and the DragonFlyBSD binary package system has had TeX Live for
    several years; they just don't include tlmgr (also true for most
    other O/S distributions).

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: beebe at math.utah.edu  -
- 155 S 1400 E RM 233                       beebe at acm.org  beebe at computer.org -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
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