Separate usb device handle from usb device. (deprecate)

third_party/libusb/libusb_send_event.patch

+diff --git a/third_party/libusb/src/libusb/core.c b/third_party/libusb/src/libusb/core.c
+index a91c77b..5512bd8 100644
+--- a/third_party/libusb/src/libusb/core.c
++++ b/third_party/libusb/src/libusb/core.c
+@@ -1664,6 +1664,15 @@ void API_EXPORTED libusb_exit(struct libusb_context *ctx)
+        free(ctx);
+ }
+ 
++/*
++ * Interrupt libusb_handle_events_timeout_completed.
++ */
++void API_EXPORTED libusb_send_event(struct libusb_context *ctx) {
++  unsigned char dummy = 1;
++  USBI_GET_CONTEXT(ctx);
++  usbi_write(ctx->ctrl_pipe[1], &dummy, sizeof(dummy));
++}
++
+ /** \ingroup misc
+  * Check if the running library has a given capability.
+  *
+diff --git a/third_party/libusb/src/libusb/libusb.h b/third_party/libusb/src/libusb/libusb.h
+index beff229..fdf0b4d 100644
+--- a/third_party/libusb/src/libusb/libusb.h
++++ b/third_party/libusb/src/libusb/libusb.h
+@@ -1350,6 +1350,11 @@ int LIBUSB_CALL libusb_pollfds_handle_timeouts(libusb_context *ctx);
+ int LIBUSB_CALL libusb_get_next_timeout(libusb_context *ctx,
+        struct timeval *tv);
+ 
++/**
++ * Interrupt libusb_handle_events_timeout_completed.
++ */
++void LIBUSB_CALL libusb_send_event(struct libusb_context *ctx);
++
+ /** \ingroup poll
+  * File descriptor for polling
+  */