Seems like wrapping the character range with square brackets is safe
for both BSD and GNU tr.  Without the brackets Solaris' tr(1) chokes
and treats - as a literal and not a range despite the man page
suggesting otherwise.

On Solaris:
$ echo 'foobar-1' | /usr/bin/tr 'a-z-' 'A-Z_'
foobAr_1

$ echo 'foobar-1' | /usr/bin/tr '[a-z]-' '[A-Z]_'
FOOBAR_1

On macOS 10.14:
$ echo 'foobar-1' | /usr/bin/tr '[a-z]-' '[A-Z]_'
FOOBAR_1

$ echo 'foobar-1' | /usr/bin/tr '[a-z]-' '[A-Z]_'
FOOBAR_1

$ gtr --version
tr (GNU coreutils) 9.3
Copyright (C) 2023 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Jim Meyering.

$ echo 'foobar-1' | /opt/local/bin/gtr '[a-z]-' '[A-Z]_'
FOOBAR_1

$ echo 'foobar-1' | /opt/local/bin/gtr '[a-z]-' '[A-Z]_'
FOOBAR_1