--- ./configure.ac.orig	2012-03-22 23:23:07.000000000 -0500
+++ ./configure.ac	2014-07-14 18:22:11.438996085 -0500
@@ -33,9 +33,7 @@
 XORG_DEFAULT_OPTIONS
 
 AC_CONFIG_HEADERS([config.h])
-
-AC_CANONICAL_HOST
-
+AC_USE_SYSTEM_EXTENSIONS
 
 AC_CHECK_HEADERS([pty.h stropts.h sys/param.h sys/select.h])
 AC_CHECK_FUNCS([select grantpt posix_openpt])
@@ -54,23 +52,16 @@
 PKG_CHECK_EXISTS(x11, [],
 	[AC_MSG_WARN([libX11 not found.  luit may not be able to find locale aliases without it.])])
 
+AC_CANONICAL_HOST
 case $host_os in
     # darwin has poll() but can't be used to poll character devices (atleast through SnowLeopard)
     darwin*)
-        OS_CFLAGS=
-        ;;
-    linux*)
-        AC_CHECK_HEADERS([poll.h])
-        AC_CHECK_FUNCS([poll])
-        OS_CFLAGS="-D_XOPEN_SOURCE=500"
         ;;
     *)
         AC_CHECK_HEADERS([poll.h])
         AC_CHECK_FUNCS([poll])
-        OS_CFLAGS=
         ;;
 esac
-AC_SUBST(OS_CFLAGS)
 
 AC_CHECK_HEADERS([pty.h stropts.h sys/ioctl.h sys/param.h sys/poll.h sys/select.h sys/time.h termios.h]) 
 AC_CHECK_FUNCS([grantpt putenv select strdup])