Can't Install ffi -v '1.9.18' on macos Catalina

To get past that error, install ffi using:

gem install ffi -v '1.9.18' -- --with-cflags="-Wno-error=implicit-function-declaration"

For those who can, I think bumping ffi version should be preferred here. bundle update ffi took me from from 1.9.18 to 1.13.1 and built successfully for me.

@denis-osmerovic, unless you have another dependency holding ffi back, you should also be able to bump ffi. Checking my dependency chain, my ffi dependency is also coming from rb-inotify 0.9.10, same as yours. The listed requirement is for ffi (>= 0.5.0, < 2), so 1.13.1 should be acceptable.

Other background:

I previously had a working copy of ffi 1.19.18, and I don't remember needing to pass any special build flags. In order to reproduce this I uninstalled and tried to reinstall that version. I'm guessing other library or toolchain updates in the meantime broke this.

I am running ruby 2.6.3 on OS X 10.15.7 alongside Xcode 12.0.1