meson: Look for FreeType using CMake too
From the commit message (split out from MR !123 (merged)):
Some systems build FreeType using CMake rather than autotools (such as Visual Studio), which will give us CMake config files rather than pkg-config files, so if we can't find FreeType using pkg-config, try again using CMake.
Please note that according to FreeType's docs/VERSIONS.TXT, the version we want when checking with CMake is 2.8.1 or later.
This separate set of checking rules are necessary as the package naming and versioning schemes are different between FreeType's .pc files and CMake config files.
With blessings, thank you!