test: win32: add linker option /ignore:4248
test: win32: add linker option /ignore:4248

It would appear that this warning (LNK4248: unresolved typedef token) is
not fixable in code, since VS CLR extensions want to create a managed type
signature for all data types, complete or not.  This unsurprisingly breaks the
C standard (or whatever close language equivalant VS uses).  This "fix" should
theoretically result in no actual runtime problems, but of course all
possibilities (esp. re: managed C++) have not been tested.

courtc/zdl,courtc/zdl