I ran into an apparently known issue with the native C compiler on OS X 10.8 not building Ruby gems correctly, so I installed GCC as suggested.
How do I have rvm rebuild all of the already-installed gems?
rvm update --rubygems 1.9.3, which seems like it should work (at least, according to the documentation), but I get the rather cryptic error message:
ERROR: rvm update has been removed. See 'rvm get' and rvm 'rubygems' CLI API instead
I have no idea what this means, and I have not been able to figure out an incantation for
get, or any other command) that recompiles my gems.