AC_CHECK_LINUX_FUNC([kernel_setsockopt],
[#include <linux/net.h>],
[kernel_setsockopt(NULL, 0, 0, NULL, 0);])
+ AC_CHECK_LINUX_FUNC([locks_lock_file_wait],
+ [#include <linux/fs.h>],
+ [locks_lock_file_wait(NULL, NULL);])
AC_CHECK_LINUX_FUNC([page_follow_link],
[#include <linux/fs.h>],
[page_follow_link(0,0);])