x11vnc: add libXtst as a dependency

x11vnc CAN be built without XTEST support, but it isn't very useful as
noted by the warning printed by configure when it isn't found:

*** A working build environment for the XTEST extension was not found ***
(libXtst).  An x11vnc built this way will be *ONLY BARELY USABLE*.
You will be able to move the mouse but not click or type.  There can
also be deadlocks if an application grabs the X server.

It is recommended that you install the necessary development packages
for XTEST (perhaps it is named something like libxtst-dev) and run
configure again.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/x11vnc/Config.in

@@ -3,6 +3,7 @@ config BR2_PACKAGE_X11VNC
 	depends on BR2_PACKAGE_XORG7
 	select BR2_PACKAGE_XLIB_LIBXT
 	select BR2_PACKAGE_XLIB_LIBXEXT
+	select BR2_PACKAGE_XLIB_LIBXTST
 	help
 	  VNC server for X11 display
 

package/x11vnc/x11vnc.mk

@@ -9,7 +9,7 @@ X11VNC_SITE = http://downloads.sourceforge.net/project/libvncserver/x11vnc/$(X11
 X11VNC_CONF_OPT = \
 	--without-avahi
 
-X11VNC_DEPENDENCIES = xlib_libXt xlib_libXext
+X11VNC_DEPENDENCIES = xlib_libXt xlib_libXext xlib_libXtst
 
 ifneq ($(BR2_INET_IPV6),y)
 # configure option only used for libvncserver