No Ruby header (ruby-devel package) in LEDE

Hi everyone, I'm trying to port on a particular LEDE device (Omega2+) a project of mine, but I'm stuck since apparently LEDE has not the ruby-devel package in any repo. Without the proper Ruby header I can't do anything - basically not even installing any native extensions.
Do you have any tip-suggestion-workaround?
Thank you.

edit /etc/opkg/distfeeds.conf and uncomment the feeds, then run

opkg update