Fix standalone build on Win64.

Win64 fires significantly more warnings than Win32. Also some recent
changes made it grumpy.

(We might want to reconsider enabling all of MSVC's warnings. Given the sorts
of warnings some of these are, I'm not sure MSVC's version of -Wall -Werror is
actually tenable. Plus, diverging from the Chromium build, especially before
the bots are ready, is going to break pretty readily.)

Change-Id: If3b8feccf910ceab4a233b0731e7624d7da46f87
Reviewed-on: https://boringssl-review.googlesource.com/3420
Reviewed-by: Adam Langley <agl@google.com>
3 files changed