Add information on compiling 32-bit Emacs on 64-bit GNU/Linux.

Update copyright for years post-Emacs 21 to present.

etc/MACHINES

 Emacs machines list
 
-Copyright (c) 1989, 1990, 1992, 1993, 1998, 2001, 2003, 2006
-Free software Foundation, Inc.
+Copyright (c) 1989, 1990, 1992, 1993, 1998, 2001, 2002, 2003, 2004,
+  2005, 2006, 2007  Free Software Foundation, Inc.
 See the end of the file for copying permissions.
 
 This is a list of the status of GNU Emacs on various machines and systems.
@@ -1458,6 +1458,17 @@ Windows NT/95/98/ME/2000
   For installation on all versions of the MS-Windows platform, see the
   file nt/INSTALL.
 
+X86_64 GNU/Linux
+
+  No special procedures should be needed to build a 64-bit Emacs.  To
+  build a 32-bit Emacs, first ensure that the necessary 32-bit system
+  libraries and include files are installed.  Then use:
+
+    env CC="gcc -m32" ./configure --build=i386-linux-gnu \
+      --x-libraries=/usr/X11R6/lib
+
+  (using the location of the 32-bit X libraries on your system).
+
 Xenix (xenix)
 
   Should work in 18.50, but you will need to edit the files

etc/PROBLEMS

@@ -2355,6 +2355,16 @@ This results from a bug in a VERY old version of GNU Sed.  To solve
 the problem, install the current version of GNU Sed, then rerun
 Emacs's configure script.
 
+*** Building a 32-bit executable on a 64-bit GNU/Linux architecture.
+
+First ensure that the necessary 32-bit system libraries and include
+files are installed. Then use:
+
+  env CC="gcc -m32" ./configure --build=i386-linux-gnu \
+    --x-libraries=/usr/X11R6/lib
+
+(using the location of the 32-bit X libraries on your system).
+
 *** Building the Cygwin port for MS-Windows can fail with some GCC version
 
 Building Emacs 22 with Cygwin builds of GCC 3.4.4-1 and 3.4.4-2 is
@@ -3687,7 +3697,7 @@ of machine defines NO_UNION_TYPE.
 
 
 Copyright 1987, 1988, 1989, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
-   2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+   2001, 2002, 2003, 2004, 2005, 2006, 2007  Free Software Foundation, Inc.
 
 Copying and redistribution of this file with or without modification
 are permitted without royalty provided this notice is preserved.