Patch to make 9term-1.6.6 build on modern Linux systems:
- Use openpty instead of /dev/pty??
- Use <errno.h>
- Use integers for font indexes to allow fonts with more than 65536
  chars (adapted from wily). 

Written by Christian Neukirchen <chneukirchen@gmail.com>, patch against 
http://archive.debian.org/debian/dists/slink/main/source/x11/9term_1.6.6.orig.tar.gz
http://archive.debian.org/debian/dists/slink/main/source/x11/9term_1.6.6-5.diff.gz

diff -aur 9term-1.6.6.old/9term/9term.h 9term-1.6.6.orig/9term/9term.h
--- 9term-1.6.6.old/9term/9term.h	2011-03-07 23:45:51.996065183 +0100
+++ 9term-1.6.6.orig/9term/9term.h	2011-03-08 00:00:54.002691256 +0100
@@ -77,7 +77,6 @@
 
 #if	defined(LINUX)
 #define	POSIXPTYS
-#define	BSDPTYS
 #endif
 
 #if	defined(RISCOS)
diff -aur 9term-1.6.6.old/9term/Make.linux 9term-1.6.6.orig/9term/Make.linux
--- 9term-1.6.6.old/9term/Make.linux	2011-03-07 23:45:51.999398452 +0100
+++ 9term-1.6.6.orig/9term/Make.linux	2011-03-06 18:56:52.402531220 +0100
@@ -20,7 +20,7 @@
 TARGET=9term
 INCLUDES=-I. -I../include
 CFLAGS=$(OS) $(INCLUDES) -fno-builtin -D_LIBXG_EXTENSION -g -O2 -Wall
-LDFLAGS=-L/usr/lib
+LDFLAGS=-L/usr/lib -lutil
 CC=gcc
 
 # change this if your X11 libraries are in different places
diff -aur 9term-1.6.6.old/9term/pty.c 9term-1.6.6.orig//9term/pty.c
--- 9term-1.6.6.old/9term/pty.c	2011-03-07 23:45:51.996065183 +0100
+++ 9term-1.6.6.orig/9term/pty.c	2011-03-08 00:01:58.231539202 +0100
@@ -499,7 +499,7 @@
 
 #endif	/* defined(RISCOS) */
 
-#ifdef OSF1
+#if OSF1 || LINUX
 /*
  *	open the master end of a pseudo-tty and return the name
  *	of the slave end (Mips/SYSV version).
diff -aur 9term-1.6.6.old/include/libg.h 9term-1.6.6.orig/include/libg.h
--- 9term-1.6.6.old/include/libg.h	1996-10-17 18:15:02.000000000 +0200
+++ 9term-1.6.6.orig/include/libg.h	2011-03-07 23:31:29.415674587 +0100
@@ -94,12 +94,12 @@
 
 struct	Subfont
 {
-	short		minrow;	/* first character row in font (for X subfonts) */
-	short		mincol;	/* first character col in font (for X subfonts) */
-	short		minchar; /* first char code in subfont */
-	short		maxchar; /* last char code in subfont */
-	short		width;	/* number of chars in row */
-	short		n;	/* number of chars in font */
+	int		minrow;	/* first character row in font (for X subfonts) */
+	int		mincol;	/* first character col in font (for X subfonts) */
+	int		minchar; /* first char code in subfont */
+	int		maxchar; /* last char code in subfont */
+	int		width;	/* number of chars in row */
+	int		n;	/* number of chars in font */
 	unsigned char	height;	/* height of bitmap */
 	char		ascent;	/* top of bitmap to baseline */
 	Fontchar	*info;	/* n+1 character descriptors */
diff -aur 9term-1.6.6.old/libframe/misc.c 9term-1.6.6.orig/libframe/misc.c
--- 9term-1.6.6.old/libframe/misc.c	1996-10-17 18:15:07.000000000 +0200
+++ 9term-1.6.6.orig/libframe/misc.c	2011-03-08 00:15:50.460177610 +0100
@@ -1,6 +1,7 @@
 /* Copyright (c) 1992 AT&T - All rights reserved. */
 #include	<u.h>
 #include	<libc.h>
+#include	<errno.h>
 #include	<pwd.h>
 #ifdef	NEEDVARARG
 #include	<varargs.h>
@@ -22,8 +23,6 @@
 
 int errstr(char *buf)
 {
-	extern int errno;
-
 	strncpy(buf, strerror(errno), ERRLEN);
 	return 1;
 }