Simplify evdev includes on FreeBSD by relying on up-to-date package

As evdev-proto is installed by CI some files have been missed:

 ../examples/pointer-constraints.c:2:10: fatal error: 'linux/input-event-codes.h' file not found
 #include <linux/input-event-codes.h>
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
 ../examples/relative-pointer-unstable-v1.c:5:10: fatal error: 'linux/input-event-codes.h' file not found
 #include <linux/input-event-codes.h>
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~

backend/session/direct-freebsd.c

@@ -1,5 +1,5 @@
 #include <assert.h>
-#include <dev/evdev/input.h>
+#include <linux/input.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>

backend/session/direct-ipc.c

@@ -1,7 +1,7 @@
 #define _POSIX_C_SOURCE 200809L
 #ifdef __FreeBSD__
 #define __BSD_VISIBLE 1
-#include <dev/evdev/input.h>
+#include <linux/input.h>
 #endif
 #include <errno.h>
 #include <fcntl.h>

backend/x11/input_device.c

@@ -2,11 +2,7 @@
 
 #include <wlr/config.h>
 
-#ifdef __linux__
 #include <linux/input-event-codes.h>
-#elif __FreeBSD__
-#include <dev/evdev/input-event-codes.h>
-#endif
 
 #include <xcb/xcb.h>
 #include <xcb/xfixes.h>

examples/idle-inhibit.c

@@ -8,11 +8,7 @@
 #include "idle-inhibit-unstable-v1-client-protocol.h"
 #include "xdg-shell-client-protocol.h"
 
-#ifdef __linux__
 #include <linux/input-event-codes.h>
-#elif __FreeBSD__
-#include <dev/evdev/input-event-codes.h>
-#endif
 
 /**
  * Usage: idle-inhibit

examples/layer-shell.c

@@ -1,9 +1,5 @@
 #define _POSIX_C_SOURCE 200112L
-#ifdef __linux__
 #include <linux/input-event-codes.h>
-#elif __FreeBSD__
-#include <dev/evdev/input-event-codes.h>
-#endif
 #include <assert.h>
 #include <GLES2/gl2.h>
 #include <limits.h>

rootston/cursor.c

@@ -7,11 +7,7 @@
 #include <wlr/util/edges.h>
 #include <wlr/util/log.h>
 #include <wlr/util/region.h>
-#ifdef __linux__
 #include <linux/input-event-codes.h>
-#elif __FreeBSD__
-#include <dev/evdev/input-event-codes.h>
-#endif
 #include "rootston/cursor.h"
 #include "rootston/desktop.h"
 #include "rootston/view.h"