diff --git a/ChangeLog b/ChangeLog
index e77dd1f4d..f9db29ad5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+20050821
+ - (dtucker) [configure.ac defines.h includes.h sftp.c] Add support for
+   LynxOS, patch from Olli Savia (ops at iki.fi).  ok djm@
+
 20050816
  - (djm) [ttymodes.c] bugzilla #1054: Fix encoding of _POSIX_VDISABLE,
    from Jacob Nevins; ok dtucker@
@@ -2941,4 +2945,4 @@
    - (djm) Trim deprecated options from INSTALL. Mention UsePAM
    - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
 
-$Id: ChangeLog,v 1.3874 2005/08/16 11:32:09 djm Exp $
+$Id: ChangeLog,v 1.3875 2005/08/22 22:06:55 dtucker Exp $
diff --git a/configure.ac b/configure.ac
index 849112829..619a4e76a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-# $Id: configure.ac,v 1.286 2005/08/16 00:48:41 tim Exp $
+# $Id: configure.ac,v 1.287 2005/08/22 22:06:56 dtucker Exp $
 #
 # Copyright (c) 1999-2004 Damien Miller
 #
@@ -555,6 +555,12 @@ mips-sony-bsd|mips-sony-newsos4)
 	AC_DEFINE(NEED_SETPRGP, [], [Need setpgrp to acquire controlling tty])
 	AC_DEFINE(HAVE_SYS_SYSLOG_H, 1, [Force use of sys/syslog.h on Ultrix])
 	;;
+
+*-*-lynxos)
+        CFLAGS="$CFLAGS -D__NO_INCLUDE_WARN__"
+        AC_DEFINE(MISSING_HOWMANY)
+        AC_DEFINE(BROKEN_SETVBUF, 1, [LynxOS has broken setvbuf() implementation])
+        ;;
 esac
 
 # Allow user to specify flags
diff --git a/defines.h b/defines.h
index 39d18e3d3..3103f8743 100644
--- a/defines.h
+++ b/defines.h
@@ -25,7 +25,7 @@
 #ifndef _DEFINES_H
 #define _DEFINES_H
 
-/* $Id: defines.h,v 1.123 2005/08/10 11:52:36 dtucker Exp $ */
+/* $Id: defines.h,v 1.124 2005/08/22 22:06:56 dtucker Exp $ */
 
 
 /* Constants */
@@ -579,6 +579,23 @@ struct winsize {
 # define SSH_SYSFDMAX 10000
 #endif
 
+#if defined(__Lynx__)
+ /*
+  * LynxOS defines these in param.h which we do not want to include since
+  * it will also pull in a bunch of kernel definitions.
+  */
+# define ALIGNBYTES (sizeof(int) - 1)
+# define ALIGN(p) (((unsigned)p + ALIGNBYTES) & ~ALIGNBYTES)
+  /* Missing prototypes on LynxOS */
+  int snprintf (char *, size_t, const char *, ...);
+  int mkstemp (char *);
+  char *crypt (const char *, const char *);
+  int seteuid (uid_t);
+  int setegid (gid_t);
+  char *mkdtemp (char *);
+  int rresvport_af (int *, sa_family_t);
+  int innetgr (const char *, const char *, const char *, const char *);
+#endif
 
 /*
  * Define this to use pipes instead of socketpairs for communicating with the
diff --git a/includes.h b/includes.h
index 89ae26d06..9408fec9a 100644
--- a/includes.h
+++ b/includes.h
@@ -21,6 +21,7 @@ static /**/const char *const rcsid[] = { (const char *)rcsid, "\100(#)" msg }
 
 #include "config.h"
 
+#include <stdarg.h>
 #include <stdio.h>
 #include <ctype.h>
 #include <errno.h>
diff --git a/sftp.c b/sftp.c
index 9f6c88fb5..f98ed7d27 100644
--- a/sftp.c
+++ b/sftp.c
@@ -1295,7 +1295,7 @@ interactive_loop(int fd_in, int fd_out, char *file1, char *file2)
 		xfree(dir);
 	}
 
-#if HAVE_SETVBUF
+#if defined(HAVE_SETVBUF) && !defined(BROKEN_SETVBUF)
 	setvbuf(stdout, NULL, _IOLBF, 0);
 	setvbuf(infile, NULL, _IOLBF, 0);
 #else