Autotools build system have been dropped. Meson is the only supported build system in HarfBuzz going forward. See https://github.com/harfbuzz/harfbuzz/releases/tag/9.0.0
Sounds like what needs to be done :) From IRC, I asked if there were any objections: 12:38:00 am - cloph_away: […] not really / wanted to look into meson anyway for the cairo update or rather to not having to deal with libtool anymore 12:39:50 am - cloph_away: but that would involve adding meson to lode for mac for example amongst other things