I don't know if there is or not, I do know that the majority of the database gems use native code. I haven't seen one yet that verifies if the libraries are there or not, it just dies when it tries to create bindings to the libraries. I'm curious to know if some else has a better answer.
I have not seen any gem yet that checks to see if the required libs are there. A case in point being the rmagick gem which needs imagemagick installed. The installation usually fails with a ruby stack trace about something missing.