[core] Update Arduino compatibility, fix MD5 library

cores/common/arduino/libraries/common/MD5/MD5.h

@@ -4,7 +4,6 @@
 
 #include <Arduino.h>
 
-#if 0 // maybe simply using void* is easier? this is not C++ so it will link anyway
 // available built-in implementations
 #if LT_ARD_MD5_POLARSSL
 #include "MD5PolarSSLImpl.h"
@@ -15,7 +14,6 @@
 #if LT_ARD_MD5_HOSTAPD
 #include "MD5HostapdImpl.h"
 #endif
-#endif
 
 // common API
 #ifdef __cplusplus

cores/common/arduino/libraries/common/MD5/MD5HostapdImpl.h

@@ -6,12 +6,12 @@
 extern "C" {
 #endif
 
-#include <stdint.h>
+struct MD5Context {
+	unsigned long buf[4];
+	unsigned long bits[2];
+	unsigned char in[64];
+};
 
-typedef uint32_t u32;
-typedef uint8_t u8;
-
-#include <crypto/md5_i.h>
 #define LT_MD5_CTX_T struct MD5Context
 
 #ifdef __cplusplus

cores/common/arduino/libraries/common/MD5/MD5MbedTLSImpl.h

@@ -6,7 +6,12 @@
 extern "C" {
 #endif
 
-#include <mbedtls/md5.h>
+typedef struct {
+	unsigned long total[2];	  /*!< number of bytes processed  */
+	unsigned long state[4];	  /*!< intermediate digest state  */
+	unsigned char buffer[64]; /*!< data block being processed */
+} mbedtls_md5_context;
+
 #define LT_MD5_CTX_T mbedtls_md5_context
 
 #ifdef __cplusplus

cores/common/arduino/libraries/common/MD5/MD5PolarSSLImpl.h

@@ -6,7 +6,12 @@
 extern "C" {
 #endif
 
-#include <polarssl/md5.h>
+typedef struct {
+	unsigned long total[2];	  /*!< number of bytes processed  */
+	unsigned long state[4];	  /*!< intermediate digest state  */
+	unsigned char buffer[64]; /*!< data block being processed */
+} md5_context;
+
 #define LT_MD5_CTX_T md5_context
 
 #ifdef __cplusplus

cores/common/arduino/src/Arduino.h

@@ -36,6 +36,7 @@ using std::min;
 
 // FreeRTOS kernel
 #include <FreeRTOS.h>
+#include <task.h>
 
 // Define available serial ports
 #if defined(__cplusplus) && LT_ARD_HAS_SERIAL