+dnl * test for in_addr_t
+dnl --------------------------------------------------
+AC_MSG_CHECKING(for in_addr_t in netinet/in.h)
+AC_EGREP_HEADER(in_addr_t, netinet/in.h,
+ [ AC_DEFINE(HAVE_IN_ADDR_T) AC_MSG_RESULT(yes) ],
+ AC_MSG_RESULT(no))
+
+dnl --------------------------------------------------
+dnl * test for Linux sendfile(2)
+dnl --------------------------------------------------
+AC_MSG_CHECKING(for sendfile in sys/sendfile.h)
+AC_EGREP_HEADER(sendfile, sys/sendfile.h,
+ [ AC_DEFINE(HAVE_LINUX_SENDFILE) AC_MSG_RESULT(yes) ],
+ AC_MSG_RESULT(no))
+
+dnl --------------------------------------------------
+dnl * test for BSD sendfile(2)
+dnl --------------------------------------------------
+AC_MSG_CHECKING(for sendfile in sys/socket.h)
+AC_EGREP_HEADER(sendfile, sys/socket.h,
+ [ AC_DEFINE(HAVE_BSD_SENDFILE) AC_MSG_RESULT(yes) ],
+ AC_MSG_RESULT(no))
+
+dnl --------------------------------------------------