[lmi] Licensing of libtiff and libjpeg-turbo

[Greg Chicares]

Apparently libtiff is free software:

https://directory.fsf.org/wiki/Libtiff
| License:Expat

Details are discussed here:
  https://lists.gnu.org/archive/html/directory-discuss/2016-03/msg00004.html

Apparently libjpeg-turbo is free software too:

https://bugzilla.mozilla.org/show_bug.cgi?id=573948
| License is wxWindows license for some parts and LGPL for the rest.

Debian provides both:
  https://packages.debian.org/buster/libjpeg-turbo-progs
  https://packages.debian.org/buster/libtiff-dev

and both are included in:
  https://www.gnu.org/software/guix/
| an advanced distribution of the GNU operating system developed by the GNU 
Project

I conclude that these are now kosher, and gnu.org distributes them anyway
with guix, so there's no objection to allowing them in our wx build. I'll
soon push updates accordingly.