The other required set of changes

As per the PR, the changes still holding it up.
Add onekey for testing.
Fix ARM builds.
Fix device descriptor when either axes or buttons is zero.
Add compile-time check for at least one axis or button.
Move definition to try to fix conflict.
PR review comments.
qmk cformat

keyboards/handwired/onekey/keymaps/joystick/config.h

@@ -0,0 +1,3 @@
+#pragma once
+#define JOYSTICK_AXES_COUNT 0
+#define JOYSTICK_BUTTON_COUNT 1

keyboards/handwired/onekey/keymaps/joystick/keymap.c

@@ -0,0 +1,5 @@
+#include QMK_KEYBOARD_H
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+  LAYOUT( JS_BUTTON0 )
+};

keyboards/handwired/onekey/keymaps/joystick/rules.mk

@@ -0,0 +1 @@
+JOYSTICK_ENABLE = yes