Win32 fixes:
- added SDO_BLOCK_SIZE macro to win32 config.h
- added explicit casts to remove compiler warnings to sdo.c
- added missing exports to Canfestival-3.def

Authors :
=========

Edouard TISSERANT (www.canfestival.org)
Francis DUPIN (LIVIC)
Laurent BESSARD (www.canfestival.org)