Add legacy ESP32 compatibility fixes

include/ArduinoEsp32Compat.h

@@ -0,0 +1,14 @@
+#pragma once
+
+// Arduino-ESP32 1.0.6 does not define these version macros, but some newer
+// libraries use them to select legacy-compatible code paths.
+#ifndef ESP_ARDUINO_VERSION
+#define EGGDUINO_LEGACY_ARDUINO_ESP32 1
+#define ESP_ARDUINO_VERSION 0
+#else
+#define EGGDUINO_LEGACY_ARDUINO_ESP32 0
+#endif
+
+#ifndef ESP_ARDUINO_VERSION_VAL
+#define ESP_ARDUINO_VERSION_VAL(major, minor, patch) (((major) * 10000) + ((minor) * 100) + (patch))
+#endif