Problems installing lgi on macOS via LuaRocks-JIT

[Peter W A Wood <peterwawood@...>]

I hope this is the right place to seek advice on installing lgi via LuaRocks-JIT. If not perhaps you could point me in the right direction.

I have recently started on the process of learning Lua and I am hoping to explore building small GUI scripts. I have GTK+3 installed on my macOS machine (using it successfully from Ruby), so I thought it would be a good idea to try out lgi.

When I tried to install lgi, I got this error:

Installing https://luarocks.org/lgi-0.9.1-1.src.rock...
Using https://luarocks.org/lgi-0.9.1-1.src.rock... switching to 'build' mode
/Applications/Xcode.app/Contents/Developer/usr/bin/make -C lgi
pkg-config --exists 'gobject-introspection-1.0 >= 0.10.8' --print-errors
Package libffi was not found in the pkg-config search path.
Perhaps you should add the directory containing `libffi.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libffi', required by 'gobject-introspection-1.0', not found
make[1]: *** [.depcheck] Error 1
make: *** [all] Error 2

Error: Build error: Failed building.

I get the same message after adding the directory containing libffi.pc to the PKG_CONFIG_PATH environment variable.

Any suggestions? 

Peter