OpenSSL is compiled with NO_RSA, no RSA operations can be used: including
key generation storage and display of RSA keys. Since these operations are
not covered by the RSA patent (my understanding is it only covers encrypt,
decrypt, sign and verify) they can be included: this is an often requested
feature, attempts to use the patented operations return an error code.

This is enabled by setting RSA_NULL. This means that if a particular application
has its own legal US RSA implementation then it can use that instead by setting
it as the default RSA method.

Still experimental and needs some fiddling of the other libraries so they have
some options that don't attempt to use RSA if it isn't allowed.