diff --git a/ChangeLog b/ChangeLog
index 9ebe265af2eaa2052ba505d0db8a796713497a84..7f2e2b3a1756a3e7f5b93a9bd8c637b25789dd68 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2005-03-17  Niels Möller  <niels@s3.kth.se>
+
+	* config.guess: Support Solaris on x86_64. Fix by Henrik
+	Grubbström. 
+
 2005-01-03  Niels Möller  <niels@s3.kth.se>
 
 	* examples/io.h: Include RSA declarations only when public key
diff --git a/config.guess b/config.guess
index 19e870b7d7752cd7d3ae583330441792b60da616..c3bae209810a008e2cb6a0c7f468cf4c9f103401 100755
--- a/config.guess
+++ b/config.guess
@@ -3,7 +3,7 @@
 #   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
 #   2000, 2001, 2002, 2003 Free Software Foundation, Inc.
 
-timestamp='2004-03-01'
+timestamp='2005-03-17'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -344,7 +344,14 @@ case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
 	echo sparc-sun-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
 	exit 0 ;;
     i86pc:SunOS:5.*:*)
-	echo i386-pc-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+       case "`optisa \`isainfo\``" in
+           amd64)
+               echo x86_64-pc-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+               ;;
+           *)
+               echo i386-pc-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
+               ;;
+       esac
 	exit 0 ;;
     sun4*:SunOS:6*:*)
 	# According to config.sub, this is the proper way to canonicalize