An OpenVMS XPG4 localization utility that merges one or more
   message text source files into a message catalog file.
   For more information on the XPG4 utilities, including file
   formats, see the Compaq C Run-Time Library Reference Manual.
   Also see help for the related commands ICONV and LOCALE.
   Format:
        GENCAT msgfile[,...] catfile
1 – Parameters
   msgfile
     The file specification of a message text source file.  The
     default file type for a message text source file is .MSGX.
   catfile
     The file specification of the message catalog file to be
     created.  If the catfile already exists, a new version is
     created that includes the messages in the existing catalog.  The
     default file type for a message catalog file is .CAT.