esp8266: do not use FlashStringHelper

ESP8266/src/iotc/arduino/comms.cpp

@@ -17,15 +17,4 @@ int mqtt_publish(IOTContextInternal *internal, const char* topic, unsigned long
     return 0;
 }
 
-void IOTC_LOG(const __FlashStringHelper *format, ...) {
-    if (getLogLevel() > IOTC_LOGGING_DISABLED) {
-        va_list ap;
-        va_start(ap, format);
-        AzureIOT::StringBuffer buffer(STRING_BUFFER_1024);
-        buffer.setLength(vsnprintf(*buffer, STRING_BUFFER_1024, (const char *)format, ap));
-        Serial.println(*buffer);
-        va_end(ap);
-    }
-}
-
 #endif // defined(ARDUINO) && defined(USE_LIGHT_CLIENT)

ESP8266/src/iotc/common/iotc_internal.h

@@ -148,14 +148,14 @@ int mqtt_publish(IOTContextInternal *internal, const char* topic, unsigned long
     const char* msg, unsigned long msg_length);
 
 #ifdef ARDUINO
-void IOTC_LOG(const __FlashStringHelper *format, ...);
-#else
 #define IOTC_LOG(...) \
     if (getLogLevel() > IOTC_LOGGING_DISABLED) { \
-        printf("  - "); \
-        printf(__VA_ARGS__); \
-        printf("\r\n"); \
+        Serial.printf("  - "); \
+        Serial.printf(__VA_ARGS__); \
+        Serial.printf("\r\n"); \
     }
+#undef F
+#define F(x) x
 #endif
 
 #ifdef __cplusplus