Implement the relative pointer protocol

A wp_relative_pointer object is an extension to the wl_pointer interface
only used for emitting relative pointer events. It will only emit events
when the parent pointer has focus.

To get a relative pointer object, use the get_relative_pointer request
of the global wp_relative_pointer_manager object.

The relative pointer protocol is currently an unstable protocol, so
unstable protocol naming conventions has been applied.

Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
diff --git a/Makefile.am b/Makefile.am
index 6d26dce..9ffe9c8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -135,7 +135,9 @@
 	protocol/viewporter-protocol.c			\
 	protocol/viewporter-server-protocol.h		\
 	protocol/linux-dmabuf-unstable-v1-protocol.c	\
-	protocol/linux-dmabuf-unstable-v1-server-protocol.h
+	protocol/linux-dmabuf-unstable-v1-server-protocol.h		\
+	protocol/relative-pointer-unstable-v1-protocol.c		\
+	protocol/relative-pointer-unstable-v1-server-protocol.h
 
 BUILT_SOURCES += $(nodist_libweston_la_SOURCES)