Many of the compatibility issues are described at
https://msdn.microsoft.com/en-us/library/mt612856.aspx. The macros
that suppressed warnings on a per-function basis no longer work in
Update 1, so replace them with #pragmas. Update 1 warns when |size_t|
arguments to |printf| are casted, so stop doing that casting.
Unfortunately, this requires an ugly hack to continue working in
MSVC 2013 as MSVC 2013 doesn't support "%zu". Finally, Update 1 has new
warnings, some of which need to be suppressed.

---

Updated by davidben to give up on suppressing warnings in crypto/x509 and
crypto/x509v3 as those directories aren't changed much from upstream. In each
of these cases, upstream opted just blindly initialize the variable, so do the
same. Also switch C4265 to level 4, per Microsoft's recommendation and work
around a bug in limits.h that happens to get fixed by Google include order
style.

(limits.h is sensitive to whether corecrt.h, pulled in by stddef.h and some
other headers, is included before it. The reason it affected just one file is
we often put the file's header first, which means base.h is pulling in
stddef.h. Relying on this is ugly, but it's no worse than what everything else
is doing and this doesn't seem worth making something as tame as limits.h so
messy to use.)

Change-Id: I02d1f935356899f424d3525d03eca401bfa3e6cd
Reviewed-on: https://boringssl-review.googlesource.com/7480
Reviewed-by: David Benjamin <davidben@google.com>