make EMS-ESP compile standalone on osx/darwin and linux

Makefile

@@ -30,7 +30,7 @@ CHECKFLAGS = -q --force --std=c++11
 #----------------------------------------------------------------------
 C_STANDARD   := -std=c17
 # CXX_STANDARD := -std=c++17
-CXX_STANDARD := -std=gnu++17
+CXX_STANDARD := -std=gnu++11
 
 # C_STANDARD   := -std=c11
 # CXX_STANDARD := -std=c++11

lib/espMqttClient/src/MqttClient.cpp

@@ -197,7 +197,7 @@ const char * MqttClient::getClientId() const {
 }
 
 void MqttClient::loop() {
-    switch (_state) {
+    switch ((State)_state) { // TOOD modified by proddy for EMS-ESP compiling on osx
     case State::disconnected:
 #if defined(ARDUINO_ARCH_ESP32)
         if (_useInternalTask == espMqttClientTypes::UseInternalTask::YES) {

lib/espMqttClient/src/MqttClient.h

@@ -123,8 +123,7 @@ class MqttClient {
 #elif defined(ARDUINO_ARCH_ESP8266) && EMC_ESP8266_MULTITHREADING
     std::atomic<bool> _xSemaphore = false;
 #elif defined(__linux__)
-    //  added mutable to compile EMS-ESP standalone
-    mutable std::mutex mtx;
+    mutable std::mutex mtx; // TOOD modified by proddy for EMS-ESP
 #endif
 
     uint8_t _rxBuffer[EMC_RX_BUFFER_SIZE];

platformio.ini

@@ -147,7 +147,7 @@ build_flags =
   -DEMSESP_DEBUG -DEMSESP_STANDALONE -DEMSESP_TEST -D__linux__
   -DEMSESP_DEFAULT_LOCALE=\"en\" -DEMSESP_DEFAULT_TX_MODE=8 -DEMSESP_DEFAULT_VERSION=\"3.6.0-dev\" -DEMSESP_DEFAULT_BOARD_PROFILE=\"S32\"
 	-lpthread
-  -std=gnu++17 -Og -ggdb
+  -std=gnu++11 -Og -ggdb
 build_src_flags =
   -Wall -Wextra -Werror -Wswitch-enum -Wno-unused-parameter -Wno-inconsistent-missing-override -Wno-unused-lambda-capture
   -Wno-missing-braces