Cleanup some stm32 warnings

platformio.ini

@@ -78,7 +78,7 @@ framework = arduino
 board = black_f407ve
 ;lib_deps = EEPROM
 board_build.core = stm32
-build_flags = -fpermissive -std=gnu++11 -UBOARD_NR_GPIO_PINS -DARDUINO_BLACK_F407VE -DCORE_STM32_OFFICIAL -DENABLE_HWSERIAL2 -DENABLE_HWSERIAL3 -DUSBCON -DHAL_PCD_MODULE_ENABLED -DUSBD_USE_CDC -DHAL_UART_MODULE_ENABLED
+build_flags = -std=gnu++11 -UBOARD_NR_GPIO_PINS -DARDUINO_BLACK_F407VE -DCORE_STM32_OFFICIAL -DENABLE_HWSERIAL2 -DENABLE_HWSERIAL3 -DUSBCON -DHAL_PCD_MODULE_ENABLED -DUSBD_USE_CDC -DHAL_UART_MODULE_ENABLED
 upload_protocol = dfu
 debug_tool = stlink
 monitor_speed = 115200

speeduino/src/PID_v1/PID_v1.cpp

@@ -300,7 +300,7 @@ bool integerPID::ComputeVVT(uint32_t Sample)
 {
    if(!inAuto) return false;
    /*Compute all the working error variables*/
-   long pTerm, iTerm, dTerm;
+   long pTerm, dTerm;
    long input = *myInput;
    long error = *mySetpoint - input;
    long dInput = error - lastError;

speeduino/src/STM32_CAN/STM32_CAN.cpp

@@ -3,16 +3,18 @@
 
 uint8_t STM32_CAN::CANMsgAvail()
 {
+  uint8_t msgAvail = CAN1->RF0R & 0x3UL; //Default value
   if (_channel == _CAN1) {
     // Check for pending FIFO 0 messages
-    return CAN1->RF0R & 0x3UL;
+    msgAvail = CAN1->RF0R & 0x3UL;
   }
   #if defined(CAN2)
   if (_channel == _CAN2) {
     // Check for pending FIFO 0 messages
-    return CAN2->RF0R & 0x3UL;
+    msgAvail = CAN2->RF0R & 0x3UL;
   }
   #endif
+  return msgAvail;
 }
 
 void STM32_CAN::CANSetGpio(GPIO_TypeDef * addr, uint8_t index, uint8_t speed )
@@ -193,6 +195,8 @@ int STM32_CAN::write(CAN_message_t &CAN_tx_msg)
     }
   }
   #endif
+
+  return -1; //Transmit failed
 }
 
 int STM32_CAN::read(CAN_message_t &CAN_rx_msg)
@@ -276,7 +280,7 @@ int STM32_CAN::read(CAN_message_t &CAN_rx_msg)
 void STM32_CAN::setBaudRate(uint32_t baud)
 {
   //there must be better way to do this, but for now it's what it is.
-  int bitrate;
+  int bitrate = 0; //Default to slowest baud rate
   switch(baud)
     {
       case 50000: