Unix install script fails on Mac

[Richard Koch]

Folks,

The MacTeX web pages are mainly about MacTeX.pkg, but we also
have a page explaining how to install TeX Live using the standard Unix
install script. Since MacTeX requires macOS 10.12 or higher, this
script will be used by those with older machines.

Today I got an error report about the current Unix install script. So I
downloaded it (first from the link on our site, and then directly from the
link on TUG's site). Sure enough; there is a problem. The console reports
the following:

Error in startup script: no such variable
    (read trace on "::env(TMPDIR)")
    invoked from within
"set ::dblfile "$::env(TMPDIR)/dblog""
    invoked from within
"if {$::tcl_platform(os) eq "Darwin"} {
  set ::dblfile "$::env(TMPDIR)/dblog"
} elseif {$::tcl_platform(platform) eq "unix"} {
  set ::dblfile "/tmp/d..."
    (file "./tlpkg/installer/install-tl-gui.tcl" line 133)

I tried several times, and the mirroring command gave
scripts dated 0627, 0629, 0630. All had the same problem.
Usually we recommend running the script as

	sudo ./install-tl --gui tcl

but in one experiment I remove the "--gui tcl" and still got
the same error.

I'm running system 10,14, Mohave, but the user is running
system 10.11, El Capitan.

Richard Koch