Sending a handler with incompatible pointer types is undefined
behavior, so this removes noop() and implements empty handlers for all
of its previous uses.
This used to work until C23.
wlopm.c: In function ‘sync_handle_done’:
wlr-output-power-management-unstable-v1.h:295:9: error: ‘new_mode’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
295 | wl_proxy_marshal((struct wl_proxy *) zwlr_output_power_v1,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
296 | ZWLR_OUTPUT_POWER_V1_SET_MODE, mode);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
wlopm.c:178:40: note: ‘new_mode’ was declared here
178 | enum zwlr_output_power_v1_mode new_mode;
| ^~~~~~~~
