Some gems need the host ruby to have shared library enabled. Currently,
we're not aware of any potential downsides to having this enabled by
default.
> Shared libraries are libraries that are loaded by programs when they
> start. When a shared library is installed properly, all programs that
> start afterwards automatically use the new shared library.
> [...] if you have a program that needs a shared library (in this case ruby
> libruby.so.2.2.0 or similar) the program will fail if it doesn't exist.
