On machines with pdflatex installed, this is run to build Theora.pdf.
Unfortunately this process breaks, at least on my Ubuntu 18.04 LTS
system. By setting `HAVE_PDFLATEX=no` (or any other value that is not
"yes") this can be avoided. I don't think that it's important to have
this PDF file built anyway, as it's not a dependency of Blender itself.
Note these are intended for platform maintainers, we do not intend to
support users making their own builds with these. For that precompiled
libraries from lib/ should be used.
Implemented by Martijn Berger, Ray Molenkamp and Brecht Van Lommel.
Differential Revision: https://developer.blender.org/D2753
