cheets: Add explicit dependency on wayland-version.h

This will fix the spurious build breakages

BUG=29996423
TEST=ninja -t query
     out/host/linux-x86/obj/EXECUTABLES/wayland_scanner_intermediates/src/scanner.o

Change-Id: I9cf728fab26239d031d1a5814e4ce560f86fbdaa
diff --git a/Android.mk b/Android.mk
index 8d1649c..60da2d0 100644
--- a/Android.mk
+++ b/Android.mk
@@ -45,6 +45,11 @@
 
 LOCAL_CFLAGS += $(WAYLAND_CFLAGS)
 
+# These files are generated, and we must make them a dependency to ensure they
+# are generated before we try to include them.
+LOCAL_ADDITIONAL_DEPENDENCIES += \
+	device/google/cheets2/external/wayland/src/wayland-version.h \
+
 LOCAL_MODULE := wayland_scanner
 LOCAL_MODULE_TAGS := optional
 include $(BUILD_HOST_EXECUTABLE)