Define v4l2 option field only if HAVE_V4L2

app/src/options.c

@@ -9,7 +9,9 @@ const struct scrcpy_options scrcpy_options_default = {
     .render_driver = NULL,
     .codec_options = NULL,
     .encoder_name = NULL,
+#ifdef HAVE_V4L2
     .v4l2_device = NULL,
+#endif
     .log_level = SC_LOG_LEVEL_INFO,
     .record_format = SC_RECORD_FORMAT_AUTO,
     .keyboard_input_mode = SC_KEYBOARD_INPUT_MODE_INJECT,

app/src/options.h

@@ -70,7 +70,9 @@ struct scrcpy_options {
     const char *render_driver;
     const char *codec_options;
     const char *encoder_name;
+#ifdef HAVE_V4L2
     const char *v4l2_device;
+#endif
     enum sc_log_level log_level;
     enum sc_record_format record_format;
     enum sc_keyboard_input_mode keyboard_input_mode;