Fix warnings found by splint (#324)

* Fix warnings found by splint

* Ignore Win32 Builder warnings about possible data loss for integers.

* Fix Windows build warnings

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

CMakeLists.txt

@@ -502,6 +502,8 @@ elseif(WIN32)
     $<$<BOOL:${BACDL_BIP}>:ws2_32>
     $<$<BOOL:${BACDL_BIP}>:iphlpapi>)
 
+  add_definitions("/W3 /D_CRT_SECURE_NO_WARNINGS /wd4244 /wd4018 /wd4267")
+
   target_sources(${PROJECT_NAME} PRIVATE
     ports/win32/bacport.h
     $<$<BOOL:${BACDL_BIP6}>:ports/win32/bip6.c>