Comment 15 for bug 290503

unrtf has a project page at savannah, here [1]. There's both a bug and a patch tracker, maybe you've got more luck there.

[1] http://savannah.gnu.org/projects/unrtf/

It seems like they added a few but not all characters, and different to your solution:
mss@otherland ~/tmp $ diff -u unrtf-0.19.3/text.c unrtf_0.19.9/text.c
--- unrtf-0.19.3/text.c 2004-02-19 00:35:04.000000000 +0100
+++ unrtf_0.19.9/text.c 2006-01-06 22:56:06.000000000 +0100
@@ -1,7 +1,6 @@
-
 /*=============================================================================
    GNU UnRTF, a command-line program to convert RTF documents to other formats.
- Copyright (C) 2000,2001 Zachary Thayer Smith
+ Copyright (C) 2000,2001,2004 by Zachary Smith

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -15,20 +14,25 @@

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

- The author is reachable by electronic mail at <email address hidden>.
+ The maintainer is reachable by electronic mail at <email address hidden>
 =============================================================================*/

 /*----------------------------------------------------------------------
  * Module name: text
- * Author name: Zach Smith
+ * Author name: Zachary Smith
  * Create date: 19 Sep 01
  * Purpose: Plain text output module
  *----------------------------------------------------------------------
  * Changes:
  * 22 Sep 01, <email address hidden>: added function-level comment blocks
+ * 29 Mar 05, <email address hidden>: changes requested by ZT Smith
+ * 14 Jun 05, <email address hidden>: higher Iso-Latin-1 characters
+ * added - thanks to <email address hidden> and
+ * <email address hidden>
+ * 23 Jul 05, <email address hidden>: added endash, emdash and bullet
  *--------------------------------------------------------------------*/

@@ -59,22 +63,24 @@

 static char*
 upper_translation_table [128] = {
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
- "?", "?", "?", "?", "?", "?", "?", "?",
+/* 0 1 2 3 4 5 6 7 */
+/* 80 */ "?", "?", "?", "?", "?", "?", "?", "?",
+/* 88 */ "?", "?", "?", "?", "?", "?", "?", "?",
+/* 90 */ "?", "?", "?", "?", "?", "?", "?", "?",
+/* 98 */ "?", "?", "?", "?", "?", "?", "?", "?",
+/* A0 */ "