Install ruby-pkg-config by entering the following commands in the terminal:
sudo apt update sudo apt install ruby-pkg-config
Description:
pkg-config implementation for Ruby
pkg-config can be used in your extconf.rb to properly detect necessary libraries for compiling native Ruby extensions, using the pkg-config database. Note that this package does not use pkg-config, only its database.
Homepage: https://github.com/ruby-gnome2/pkg-config
Version: 1.2.9-1
Section: universe/ruby