1.0.41.45: make.sh command-line parsing

1.0.41.45: make.sh command-line parsing

 Based on patches by Daniel Herring:

 * Simple --option and --option=arg command-line parser in make.sh.

 * Supported options:

   ** --xc-host=<command> to specify XC host option instead of a
      positional argument. (Incompatible change!)

   ** --prefix=<path> to specify a non-standard install location for
      both build and install.sh.

      Addresses https://bugs.launchpad.net/sbcl/+bug/550889

   ** --help

 Semi-related minor cleanup:

 * Use --no-userinit and --no-sysinit instead of version.lisp-expr as
   the default inits for self-building: they have been around long
   enough now that it should not stop anyone from building, and makes
   for a somewhat less magical looking "//Build options: ..." line in
   the build log.