- Add xt to USE_XORG modules

This should work around the recent problem in which ports depending on Tk 8.6
  failed to to locate the X11 include directory. The reason behind this is that
  TEA [1] looks for X11/Intrinsic.h, which is installed by xt.

x11-toolkits/tk86/Makefile

@@ -3,7 +3,7 @@
 
 PORTNAME=	tk
 PORTVERSION=	8.6.0
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	x11-toolkits
 MASTER_SITES=	SF/tcl/Tcl/${PORTVERSION} \
 		${MASTER_SITE_TCLTK}
@@ -28,7 +28,7 @@ INSTALL_TARGET=	install
 
 USE_LDCONFIG=	yes
 USE_TCL=	${SHORT_TK_VER}
-USE_XORG=	x11
+USE_XORG=	x11 xt
 GNU_CONFIGURE=	yes
 CONFIGURE_ARGS=	--enable-shared \
 		--enable-man-suffix=.${MAN_SUFFIX} \