Add implementations of open(2), mkdir(2), stat(2),
etc. that support long paths under Windows (paths
longer than MAX_PATH in <windows.h>, which is 260
characters).
The implementations are in a separate namespace
(google::protobuf::internal::win32), so they won't
collide with the standard implementations in
<io.h>, but after importing them with `using` they
can be drop-in replacements.
Fixes https://github.com/bazelbuild/bazel/issues/2634
Fixes https://github.com/google/protobuf/issues/2891
When trying to compile the protobuf code as a DLL, and then compile other DLLs
with generated .pb.cc/h files that reference
InternalMetadataWithArena::InternalMetadataWithArena(Arena*), MSVC gives an
"unresolved external symbol" error. This seems to be due to the function being
simultaneously exported and inline. Moving it out-of-line fixes things.
There are other functions exported and inline as well but de-inlining them
doesn't seem to be necessary to get the build working, and I'd rather de-inline
as few functions as possible.