$ sudo gem install sassc -v '2.2.1'
Building native extensions. This could take a while...
ERROR:  Error installing sassc:
	ERROR: Failed to build gem native extension.

    current directory: /var/lib/gems/2.5.0/gems/sassc-2.2.1/ext
/usr/bin/ruby2.5 -r ./siteconf20200326-14287-1naeh6u.rb extconf.rb
creating Makefile

current directory: /var/lib/gems/2.5.0/gems/sassc-2.2.1/ext
make "DESTDIR=" clean

current directory: /var/lib/gems/2.5.0/gems/sassc-2.2.1/ext
make "DESTDIR="
compiling ./libsass/src/memory/SharedPtr.cpp
make: g++: Command not found
Makefile:234: recipe for target 'SharedPtr.o' failed
make: *** [SharedPtr.o] Error 127

make failed, exit code 2

Gem files will remain installed in /var/lib/gems/2.5.0/gems/sassc-2.2.1 for inspection.
Results logged to /var/lib/gems/2.5.0/extensions/x86_64-linux/2.5.0/sassc-2.2.1/gem_make.out