Update to 1.12.3.

*** 1,9 ****
! /*      $Id: main.c,v 1.165 2011/10/06 22:29:12 kristaps Exp $ */
  /*
   * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
!  * Copyright (c) 2010, 2011 Ingo Schwarze <schwarze@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
--- 1,9 ----
! /*      $Id: main.c,v 1.167 2012/11/19 17:22:26 schwarze Exp $ */
  /*
   * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
!  * Copyright (c) 2010, 2011, 2012 Ingo Schwarze <schwarze@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
*** 83,92 ****
--- 83,93 ----
  {
          int              c;
          struct curparse  curp;
          enum mparset     type;
          enum mandoclevel rc;
+         char            *defos;
  
          progname = strrchr(argv[0], '/');
          if (progname == NULL)
                  progname = argv[0];
          else
*** 95,108 ****
          memset(&curp, 0, sizeof(struct curparse));
  
          type = MPARSE_AUTO;
          curp.outtype = OUTT_ASCII;
          curp.wlevel  = MANDOCLEVEL_FATAL;
  
          /* LINTED */
!         while (-1 != (c = getopt(argc, argv, "m:O:T:VW:")))
                  switch (c) {
                  case ('m'):
                          if ( ! moptions(&type, optarg))
                                  return((int)MANDOCLEVEL_BADARG);
                          break;
                  case ('O'):
--- 96,123 ----
          memset(&curp, 0, sizeof(struct curparse));
  
          type = MPARSE_AUTO;
          curp.outtype = OUTT_ASCII;
          curp.wlevel  = MANDOCLEVEL_FATAL;
+         defos = NULL;
  
          /* LINTED */
!         while (-1 != (c = getopt(argc, argv, "I:m:O:T:VW:")))
                  switch (c) {
+                 case ('I'):
+                         if (strncmp(optarg, "os=", 3)) {
+                                 fprintf(stderr, "-I%s: Bad argument\n",
+                                                 optarg);
+                                 return((int)MANDOCLEVEL_BADARG);
+                         }
+                         if (defos) {
+                                 fprintf(stderr, "-I%s: Duplicate argument\n",
+                                                 optarg);
+                                 return((int)MANDOCLEVEL_BADARG);
+                         }
+                         defos = mandoc_strdup(optarg + 3);
+                         break;
                  case ('m'):
                          if ( ! moptions(&type, optarg))
                                  return((int)MANDOCLEVEL_BADARG);
                          break;
                  case ('O'):
*** 123,133 ****
                  default:
                          usage();
                          /* NOTREACHED */
                  }
  
!         curp.mp = mparse_alloc(type, curp.wlevel, mmsg, &curp);
  
          /*
           * Conditionally start up the lookaside buffer before parsing.
           */
          if (OUTT_MAN == curp.outtype)
--- 138,148 ----
                  default:
                          usage();
                          /* NOTREACHED */
                  }
  
!         curp.mp = mparse_alloc(type, curp.wlevel, mmsg, &curp, defos);
  
          /*
           * Conditionally start up the lookaside buffer before parsing.
           */
          if (OUTT_MAN == curp.outtype)
*** 150,159 ****
--- 165,175 ----
  
          if (curp.outfree)
                  (*curp.outfree)(curp.outdata);
          if (curp.mp)
                  mparse_free(curp.mp);
+         free(defos);
  
          return((int)rc);
  }
  
  static void
*** 168,183 ****
  usage(void)
  {
  
          fprintf(stderr, "usage: %s "
                          "[-V] "
!                         "[-foption] "
                          "[-mformat] "
                          "[-Ooption] "
                          "[-Toutput] "
!                         "[-Wlevel] "
!                         "[file...]\n", 
                          progname);
  
          exit((int)MANDOCLEVEL_BADARG);
  }
  
--- 184,199 ----
  usage(void)
  {
  
          fprintf(stderr, "usage: %s "
                          "[-V] "
!                         "[-Ios=name] "
                          "[-mformat] "
                          "[-Ooption] "
                          "[-Toutput] "
!                         "[-Wlevel]\n"
!                         "\t      [file ...]\n", 
                          progname);
  
          exit((int)MANDOCLEVEL_BADARG);
  }