By default the package detects the presence of pdflatex and builds documentation automatically.
During the OpenWrt build this behavior is not acceptable. The added patch introduces a configure
option to explicitly enable the build of the documentation on request.

Signed-off-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>

Since the current release of the package does not provide
configure options to disable these dependencies, a patch is necessary.

Signed-off-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>