AC_CHECK_FUNCS(sigaction strerror strsignal pread sys_siglist _sys_siglist getdents mctl prctl sendmsg inet_ntop if_indextoname)
AC_CHECK_HEADERS([sys/reg.h sys/filio.h sys/acl.h sys/asynch.h sys/door.h stropts.h sys/conf.h sys/stream.h sys/tihdr.h sys/tiuser.h sys/sysconfig.h ioctls.h sys/ioctl.h sys/ptrace.h termio.h linux/ptrace.h asm/reg.h sys/uio.h sys/aio.h poll.h sys/poll.h sys/vfs.h asm/sysmips.h linux/utsname.h sys/nscsys.h mqueue.h sys/epoll.h libaio.h inttypes.h], [], [])
AC_CHECK_HEADERS([linux/icmp.h linux/in6.h linux/netlink.h linux/if_packet.h],
- [], [], [#include <linux/socket.h>])
+ [], [], [#include <stddef.h>
+#include <linux/socket.h>])
AC_CHECK_HEADERS([asm/sigcontext.h], [], [], [#include <signal.h>])
AC_CHECK_HEADERS([netinet/tcp.h netinet/udp.h],,, [#include <netinet/in.h>])