package/matchbox: enable support for the Xsession manager

Since this is a non-obvious dependency, just select the appropriate
library.

Also, add a comment to act as a separator between matchbox' options
and the other matchbox packages.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/matchbox/Config.in

@@ -17,6 +17,14 @@ menuconfig BR2_PACKAGE_MATCHBOX
 
 if BR2_PACKAGE_MATCHBOX
 
+config BR2_PACKAGE_MATCHBOX_SM
+	bool "session manager"
+	select BR2_PACKAGE_XLIB_LIBSM
+	help
+	  Enable support for the Session Manager.
+
+comment "matchbox utilities"
+
 source "package/matchbox-common/Config.in"
 source "package/matchbox-desktop/Config.in"
 source "package/matchbox-fakekey/Config.in"

package/matchbox/matchbox.mk

@@ -27,4 +27,11 @@ else
 MATCHBOX_CONF_OPTS += --disable-startup-notification
 endif
 
+ifeq ($(BR2_PACKAGE_MATCHBOX_SM),y)
+MATCHBOX_CONF_OPTS += --enable-session
+MATCHBOX_DEPENDENCIES += xlib_libSM
+else
+MATCHBOX_CONF_OPTS += --disable-session
+endif
+
 $(eval $(autotools-package))