Fail on unsupported HID option

If the feature is not supported on the platform, fail during command
line parsing instead of using a fallback.

app/src/cli.c

@@ -1300,7 +1300,13 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
                 args->help = true;
                 break;
             case 'K':
+#ifdef HAVE_AOA_HID
                 opts->keyboard_input_mode = SC_KEYBOARD_INPUT_MODE_HID;
+#else
+                LOGE("HID over AOA (-K/--hid-keyboard) is not supported on "
+                     "this platform. It is only available on Linux.");
+                return false;
+#endif
                 break;
             case OPT_MAX_FPS:
                 if (!parse_max_fps(optarg, &opts->max_fps)) {

app/src/scrcpy.c

@@ -534,8 +534,8 @@ scrcpy(struct scrcpy_options *options) {
     struct sc_mouse_processor *mp = NULL;
 
     if (options->control) {
-        if (options->keyboard_input_mode == SC_KEYBOARD_INPUT_MODE_HID) {
 #ifdef HAVE_AOA_HID
+        if (options->keyboard_input_mode == SC_KEYBOARD_INPUT_MODE_HID) {
             bool aoa_hid_ok = false;
 
             bool ok = sc_aoa_init(&s->aoa, serial, acksync);
@@ -566,13 +566,10 @@ aoa_hid_end:
                      "(-K/--hid-keyboard ignored)");
                 options->keyboard_input_mode = SC_KEYBOARD_INPUT_MODE_INJECT;
             }
+        }
 #else
-            LOGE("HID over AOA is not supported on this platform, "
-                 "fallback to default keyboard injection method "
-                 "(-K/--hid-keyboard ignored)");
-            options->keyboard_input_mode = SC_KEYBOARD_INPUT_MODE_INJECT;
+        assert(options->keyboard_input_mode != SC_KEYBOARD_INPUT_MODE_HID);
 #endif
-        }
 
         // keyboard_input_mode may have been reset if HID mode failed
         if (options->keyboard_input_mode == SC_KEYBOARD_INPUT_MODE_INJECT) {