diff -d -urpN uClibc.5/libc/sysdeps/linux/x86_64/bits/wordsize.h uClibc.6/libc/sysdeps/linux/x86_64/bits/wordsize.h
--- uClibc.5/libc/sysdeps/linux/x86_64/bits/wordsize.h	2009-06-27 00:46:21.000000000 +0200
+++ uClibc.6/libc/sysdeps/linux/x86_64/bits/wordsize.h	2009-11-26 13:48:49.867844274 +0100
@@ -2,7 +2,8 @@
 
 #if defined __x86_64__
 # define __WORDSIZE	64
-/*# define __WORDSIZE_COMPAT32	1*/
+/* This makes /var/run/utmp compatible with 32-bit environment: */
+# define __WORDSIZE_COMPAT32	1
 #else
 # define __WORDSIZE	32
 #endif