Compilation failure with nmake and MSTDC = no in HEAD

Hi all,

I noticed that the build with nmake is broken when using MSDTC = no
becaus of e85fbb (libpq switch):
setup.c(448) : warning C4013: 'CALL_GetTransactionObject' undefined;
assuming extern returning int
setup.c(448) : warning C4047: '=' : 'void *' differs in levels of
indirection from 'int'
setup.c(465) : warning C4013: 'CALL_ReleaseTransactionObject'
undefined; assuming extern returning int
Attached is a patch fixing the problem, simplifying at the same time
test_connection in setup.c where I think the boolean flag withDtc is
not needed.
Regards,
--
Michael