Use __disable_irq() and __enable_irq(), to make it clear code is not portable

Author: sandeepmistry

cores/arduino/USB/CDC.cpp

@@ -303,15 +303,15 @@ int32_t Serial_::readBreak() {
 	// disable interrupts,
 	// to avoid clearing a breakValue that might occur 
 	// while processing the current break value
-	noInterrupts();
+	__disable_irq();
 
 	int32_t ret = breakValue;
 
 	breakValue = -1;
 
 	if (enableInterrupts) {
 		// re-enable the interrupts
-		interrupts();
+		__enable_irq();
 	}
 
 	return ret;