esp32: replace port with PlatformIO implementation and add CI build (#1292)

ports/esp32/src/mstimer_init.h

@@ -0,0 +1,32 @@
+/**
+ * @file
+ * @brief BACnet millisecond timer hook declarations for the PlatformIO ESP32
+ * port
+ * @author Kato Gangstad
+ */
+
+#ifndef M5STAMPLC_MSTIMER_INIT_H
+#define M5STAMPLC_MSTIMER_INIT_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Initialize the system timer services used by BACnet
+ */
+void systimer_init(void);
+
+/**
+ * @brief Get the current millisecond tick count
+ * @return milliseconds since startup
+ */
+unsigned long mstimer_now(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif