* build: require unibilium>=2.0
This also ports FindUnibilium to LibFindMacros, which was planned
anyway, and makes the version check easier.
With an older Unibilium our fallback code in `terminfo_from_builtin`
will not work (because it assumes the new data structures from 2.0.0 [1]),
and nvim would crash later because of `ut` being NUL.
1: 42f3cdd284
The variables are not meant to be defined there really, but only with
the third-party project.
Using them, e.g. with the following, would actually result in libvterm
not being found then:
make CMAKE_EXTRA_FLAGS="-DUSE_BUNDLED_LIBVTERM=ON" \
DEPS_CMAKE_FLAGS="-DUSE_BUNDLED=OFF -DUSE_BUNDLED_LIBVTERM=ON"
In https://github.com/neovim/neovim/pull/6357 they were renamed to
`USE_BUNDLED_X` from `X_USE_BUNDLED`, but the above reasoning applies
to the old names, too.
Internally `CMAKE_PREFIX_PATH` is used to add the built/bundled third
party packages for `find_package`, so there is no reason to e.g. query
the values via `load_cache` for example from the third-party project.
The package argument is case sensitive, which is important to handle
X_FIND_REQUIRED properly, i.e. error out early if it is not found:
CMake Error at /usr/share/cmake-3.14/Modules/FindPackageHandleStandardArgs.cmake:137 (message):
Could NOT find Unibilium (missing: UNIBILIUM_LIBRARY UNIBILIUM_INCLUDE_DIR)
Otherwise it would continue until:
CMake Error: The following variables are used in this project, but they
are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the
CMake files:
UNIBILIUM_INCLUDE_DIR (ADVANCED)
Quickly checked via `rg 'find_package_handle_standard|find_package.*REQUIRED' -I | sort`.
Ref: https://gitlab.kitware.com/cmake/cmake/issues/19413
