make Ben's cool range select hack work with Push 2

libs/surfaces/push2/buttons.cc

@@ -364,6 +364,17 @@ Push2::button_play ()
 		return;
 	}
 
+	if (_modifier_state & ModSelect) {
+		if (in_range_select) {
+			in_range_select = true;
+			access_action ("Editor/start-range-from-playhead");
+		} else {
+			access_action ("Editor/finish-range-from-playhead");
+			in_range_select = false;
+		}
+		return;
+	}
+
 	if (session->transport_rolling ()) {
 		transport_stop ();
 	} else {

libs/surfaces/push2/push2.cc

@@ -104,6 +104,7 @@ Push2::Push2 (ARDOUR::Session& s)
 	, _pressure_mode (AfterTouch)
 	, selection_color (LED::Green)
 	, contrast_color (LED::Green)
+	, in_range_select (false)
 {
 
 	build_maps ();

libs/surfaces/push2/push2.h

@@ -599,6 +599,8 @@ class Push2 : public ARDOUR::ControlProtocol
 
 	uint8_t selection_color;
 	uint8_t contrast_color;
+
+	bool in_range_select;
 };
 
 } /* namespace */