Introduce little endian RISC support

Little endian RISC support was either not or incorrectly implemented in AES.
This was avoided by always depending on the CICS implementations for LE.
These additions and fixes add the LE RISC support in AES and allow configure
to set the conditions for it.
The configure script is auto-generated.  Since your pull request doesn't include changes to configure.in, these changes will not persist the next time configure.in is updated.