Windows warnings from VS 2017

I'm working through testing the changes to allow building with Visual
Studio 2017. I've noticed that there are some warnings that we don't see
in earlier compilers.

First, it warns about a couple of unused variables at lines 4553 and
4673 of src/backend/optimizer/path/costsize.c. I think we can do a
little rearrangement to keep it happy there.

It's also warning that it will copy 16 bytes to a 13 byte structure at
lines 518, 1293 and 1294 of src/backend/commands/dbcommands.c. I haven't
seen any ill effects of this so far, but it seems to indicate that
something is possibly amiss on this compiler with the MemSet macros.

The regression tests are currently failing on my test platform (Windows
Server 2016) because it says it can't change permissions on the
testtablespace directory. I have no idea what's going on there, still
investigating.

cheers

andrew

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Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services