The documentation currently fails to build on Jenkins due to
hyperref and doxygen not playing nicely with each other on
Debian Stretch.

The jenkins autotools build has never worked because we try to
build against uninstalled versions of the opus and ogg libraries,
whose pkg-config files export a static library. This works fine
for executables, but libtool seemingly can't link a dynamic library
against a static library.

We could change the -uninstalled.pc files to reference the libtool
versions of the libraries, but that breaks the unix makefile builds,
which of course don't use libtool.

As a work around, write out our own versions of the pc files and
use those to reference the file we need.

Also sets -x on both continuous integration scripts so it's more
clear what steps are being applied.

We use scripts like these with jenkins to do automatic build
and test runs on every commit. Keeping the build instructions
in the source repository itself makes it easier to track changes,
and easier to make atomic updates when something is moved in
the build system which breaks the jenkins runs.