[tex-live] kpathsea header and library

[Karl Berry]

    I was hoping there was a way to get the necessary
    "development" files for kpathsea without checking out all
    of TL. 

It's theoretically possible but practically painful to finagle this.
There is no simple recipe.
  https://tug.org/texlive/doc/tlbuild.html#Build-one-package 
discusses it, the paragraph towards the bottom starting
"Finally, the above retrieves ...".

    I've since installed texlive-kpathsea-lib rpms on my
    Centos system and lcdf-typetools seems satisfied with them
    although they apparently date back to 2015.

Good. Not much has changed since 2015 (or a lot earlier than that :).
--best, karl.