--- Makefile.in.orig	2008-11-08 20:32:00.000000000 +0100
+++ Makefile.in	2008-11-08 20:32:22.000000000 +0100
@@ -123,7 +123,7 @@
 
 byteswap.h: byteswap.in.h
 	{ echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
-	  cat $(srcdir)/byteswap.in.h; \
+	  cat $(top_srcdir)/byteswap.in.h; \
 	} > $@-t
 	mv -f $@-t $@