mupdf: Remove unused dependencies

This removes all the mupdf dependencies, because they were not used.

mupdf ships with bundled versions of all the required libs in the directory thirdparty and those are used, even if the dependencies are specified.

In addition to that all the environment flag stuff was broken and mupdf was doing a debug build, so I removed those and properly enabled a release build.

I compared the build logs of both versions of the formula and they both compile the same files, including all of the bundled third-party libs.