Each major target of polybar can now be enabled/disabled while
configuring (even polybar itself).
The cmake code specific to each target will only run if the target is
enabled.
This allows us to for example just build the documentation without
having to run all the cmake code related to compilation or having the
polybar dependencies installed (other than sphinx).
They were required before, but could technically be deactived (the
compilation would fail, but configuration was possible).
The WITH_XRANDR and WITH_XCOMPOSITE now no longer appear in the cmake
part. It still appears in the source code, but is always set to 1
Fixes#1536
* Use GNUInstallDirs instead of hardcoded paths
This change should be a no-op in the normal case and at the same time make it
easier to customise polybar builds on systems with special needs.
* Avoid creating /usr/share/doc/polybar/polybar/*
* Include GNUInstallDirs for the doc target itself
* cmake: Don't try to set CMAKE_INSTALL_* variables
Since we include GNUInstallDirs all these variables are already set
* cmake: Print install directories in summary
* fix(cmake): Make doc-only work like normal build
This is kind of a dirty hack to force CMAKE_INSTALL_DOCDIR to use
`polybar` as the project name when only polybar-doc is built.
Maybe it is wiser at some point to be able to do a doc only build (and
install) that can be done from the top level project. Then we would also
not need to include GNUInstallDirs here
