Gentoo doesn't have a separate synctex package (it's part of the large
texlive-core package), and we'd prefer to use the internal code to avoid
the dependency.
This option lets us ensure that we will always use the internal synctex
code, regardless of whether synctex is available on the system.
Epiphany deprecated support for NPAPI for 3.30, and when enabled
manually it will not download the PDF document from the network.
Therefore, it does not make sense to keep the browser-plugin
anymore.
Fixes#968
Meson is a build system focused on speed and ease of use, which
helps speed up software development. This patch adds Meson support
alongside Autotools.