Otherwise it won't compile. I guesss this used to work because
<asm/page.h> was included somewhere to get the BUG macros, but now with
the advent of <asm/bug.h> that's changed.
diff -ruN -X../cludes linux-2.5.59-uc0.orig/fs/seq_file.c linux-2.5.59-uc0/fs/seq_file.c
--- linux-2.5.59-uc0.orig/fs/seq_file.c 2002-09-18 09:59:04.000000000 +0900
+++ linux-2.5.59-uc0/fs/seq_file.c 2003-01-22 11:49:41.000000000 +0900
@@ -10,6 +10,7 @@
#include <linux/slab.h>
#include <asm/uaccess.h>
+#include <asm/page.h>
/**
* seq_open - initialize sequential file