Feature/bip6 win32 debug enhancements (#212)

* Move win32 specific checks to bacport.h module

* Create IPv6 snprintf function in bvlc6.c module

* Improve BIP6 debug for win32 port

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>

src/bacnet/basic/object/gateway/gw_device.c

@@ -62,12 +62,6 @@
 /* os specfic includes */
 #include "bacnet/basic/sys/mstimer.h"
 
-#if defined(__BORLANDC__) || defined(_WIN32)
-/* seems to not be defined in time.h as specified by The Open Group */
-/* difference from UTC and local standard time  */
-long int timezone;
-#endif
-
 /* local forward and external prototypes */
 extern int Device_Read_Property_Local(BACNET_READ_PROPERTY_DATA *rpdata);
 extern bool Device_Write_Property_Local(BACNET_WRITE_PROPERTY_DATA *wp_data);