Add libpulse dependency for sdl

[kevingranade]

Summary

SUMMARY: None

Purpose of change

Build fix for clang-tidy build, see e.g. https://travis-ci.org/CleverRaven/Cataclysm-DDA/jobs/624829027

Testing

Just needs to build cleanly.

Additional context

Some other build stages may need the same treatment.

[kevingranade]

Still broken, I'm not clear how to resolve this, will need to investigate some more:

The following packages have unmet dependencies:

 libpulse-dev : Depends: libpulse0 (= 1:8.0-0ubuntu3.10) but 1:8.0-0ubuntu3.11 is to be installed

                Depends: libpulse-mainloop-glib0 (= 1:8.0-0ubuntu3.10) but it is not going to be installed

E: Unable to correct problems, you have held broken packages.
apt-get.diagnostics

apt-get install failed

The command "sudo -E apt-get -yq --no-install-suggests --no-install-recommends $(travis_apt_get_options) install clang-8 libclang-8-dev llvm-8-dev llvm-8-tools libsdl2-dev libsdl2-ttf-dev libsdl2-image-dev libsdl2-mixer-dev libpulse-dev" failed and exited with 100 during .

[jbytheway]

I believe #36131 is a working version of this. Looks like Travis has provided an updated libpulse but not libpulse-dev in their tweaks to the standard Xenial, so you need to explicitly specify a lower version of libpulse to trigger a downgrade.

[ZhilkinSerg]

Closing in favor of #36131.