If the <sourcefile> in question exists in the current directory,
      then it is used, and RCS is not called into play.

      If <sourcefile> is still unresolved, and you have a child
      subdirectory in your source directory named RCS, then that
      directory will be searched for <sourcefile>. If <sourcefile> is
      found there, it is checked out and used.

      If <sourcefile> is still unresolved, and you have a file named RCS
      in your source directory, then that file should contain the full
      drive and directory of where the RCS files are stored. This
      'pointed to' directory is then searched for <sourcefile>. If
      <sourcefile> is found there, it is checked out and used.

      If <sourcefile> is still unresolved, the RCSDIR environment
      directive is checked. If the RCSDIR environment variable exists,
      the directory it points to is searched for the file. If
      <sourcefile> is found there, it is checked out and used.

      If <sourcefile> is still unresolved, then it is reported as
      missing.