The 1973 MUDDLE; TS MIDAS binary has these four instruction aliases with
SI at the end (and they weren't used in the 1973 Muddle at all). All
later versions of MIDAS use RI names, as does more recent Muddle source,
so this must have been patched in later.
Older versions of MIDAS expect you to type a command at them, which
makes them hard to automate with :x or XFILEs. This patch backports the
JCLINI code from later versions of MIDAS, which pre-stuffs the command
buffer with the JCL string if available.
