New review comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/31671#discussion_r659257712

Comment:
The pkg config file has: `includedir=${prefix}/include`, which is either wrong or incompatible with what `foot` expects.

https://github.com/JuliaLang/julia/blob/d7d2b0c692eb6ad409d7193ba8d9d42972cbf182/src/flisp/julia_extensions.c#L6 uses it like foot does, so that's the "correct" usage. And we pass a similar arg in the Julia template: `UTF8PROC_INC='${XBPS_CROSS_BASE}/usr/include/libutf8proc'`

I will try to patch the pc file and see if our other packages don't break (they almost certainly won't, since `-I/usr/include` is a compiler default and any package doing `#include "libutf8proc/utf8proc.h"` will just keep working). From what I can see, it's our package that's doing broken stuff, since we move the header into a directory but didn't change what the pkg-config file does (the file is in `srcpkgs/libut8proc/files` ;)

https://github.com/JuliaStrings/utf8proc looks even more attractive now, since it ships with its own pc file.

Regarding this specific PR, for accuracy the comment should be `FIXME: our pkg-config file for utf8proc sets the wrong include dir`