Allow to build with the PyPI package "clang" instead of "libclang". 1. It seems to be maintained. 2. In the FreeBSD base system there is no pre-built libclang.so. If you need this library you have to install llvm from ports additionally. 2. On FreeBSD there is no pre-built wheel "libclang" with a packaged libclang.so.

This is a 'dumb' version of Charis SIL, created by taking the
plain glyphs from the design source postscript outlines and stripping
away all of the OpenType smarts and only including the basic character
set needed to cover the common Latin, Greek, and Cyrillic encodings.