If ragel 6.10 is not found, build it from source.
Seems to work, except that ragel uses exceptions and we configure
HarfBuzz build to not use exceptions, and I can’t find away to enable
exceptions only for the ragel subproject. I had to remove cpp_eh=none
from default options and try to disable exceptions in MSVC manually
(other compilers are already handled).
We don’t currently use it anywhere. It was used briefly for the
hb-fc-list tool, but this tool have not been built since 2015:
commit cd042fc8c4
Author: Behdad Esfahbod <behdad@behdad.org>
Date: Thu Jun 18 10:55:13 2015 -0700
[util] Disable hb-fc-list for now
Until I figure out what to do about the API, and finalize
the tool.
Garret Rieger
Khaled Hosny
Ebrahim Byagowi
Mathieu Duponchelle