Add makefile rule to copy headers from kernel tree
diff --git a/configure.ac b/configure.ac
index 410a359..cece9f8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -188,6 +188,11 @@
 
 AM_CONDITIONAL(HAVE_INTEL, [test "x$INTEL" != "xno"])
 
+AC_ARG_WITH([kernel-source],
+            [AS_HELP_STRING([--with-kernel-source],
+              [specify path to linux kernel source])],
+	    [kernel_source="$with_kernel_source"])
+AC_SUBST(kernel_source)
 
 AC_SUBST(WARN_CFLAGS)
 AC_OUTPUT([