Fix semi-blocking read mode problem with timeouts on Windows

src/main/c/Windows/SerialPort_Windows.c

@@ -2,7 +2,7 @@
  * SerialPort_Windows.c
  *
  *       Created on:  Feb 25, 2012
- *  Last Updated on:  Jul 27, 2018
+ *  Last Updated on:  Sep 25, 2018
  *           Author:  Will Hedgecock
  *
  * Copyright (C) 2012-2018 Fazecast, Inc.
@@ -477,7 +477,7 @@ JNIEXPORT jboolean JNICALL Java_com_fazecast_jSerialComm_SerialPort_configTimeou
 		case (com_fazecast_jSerialComm_SerialPort_TIMEOUT_READ_SEMI_BLOCKING | com_fazecast_jSerialComm_SerialPort_TIMEOUT_WRITE_BLOCKING):		// Read Semi-blocking/Write Blocking
 			timeouts.ReadIntervalTimeout = MAXDWORD;
 			timeouts.ReadTotalTimeoutMultiplier = MAXDWORD;
-			timeouts.ReadTotalTimeoutConstant = readTimeout;
+			timeouts.ReadTotalTimeoutConstant = readTimeout ? readTimeout : 0x0FFFFFFF;
 			timeouts.WriteTotalTimeoutConstant = writeTimeout;
 			break;
 		case com_fazecast_jSerialComm_SerialPort_TIMEOUT_READ_BLOCKING:		// Read Blocking