[mlir] Add header file for ssize_t

[ashay-github]

Summary

ssize_t is part of POSIX and not standard C/C++, so using ssize_t
without the necessary header files causes the build to fail on Windows
with the following error: 'ssize_t': undeclared identifier.

This patch includes llvm/Support/DataTypes.h to resolve the problem.

[zero9178]

I think the correct header to include ssize_t seems to be llvm/Support/DataTypes.h, based on other usage throughout MLIR and LLVM. It defines ssize_t on Windows without including any Windows headers as well, which should generally be avoided from within headers (since they massively pollute the global namespace and even have hostile macro defines).

Also for future reference, Windows specific code should be guarded by the _WIN32 define, not _MSC_VER.

[ashay-github]

Thanks @zero9178! Updated the commit to incldue DataTypes.h.

[zero9178]

LGTM thanks!

[ashay-github]

Thanks @zero9178! Would you be willing to land this change please? I don't have commit access.

[zero9178]

In D141149#4032326, @ashay-github wrote:

Thanks @zero9178! Would you be willing to land this change please? I don't have commit access.

Sure. What git name and email should I use to author the commit?

[ashay-github]

Thanks! Could you attribute it to "Ashay Rane <[e-mail]>"?

mlir/lib/Bindings/Python/PybindUtils.h

 //===- PybindUtils.h - Utilities for interop with pybind11 ------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef MLIR_BINDINGS_PYTHON_PYBINDUTILS_H
 #define MLIR_BINDINGS_PYTHON_PYBINDUTILS_H
 
 #include "mlir-c/Support.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/DataTypes.h"
 
 #include <pybind11/pybind11.h>
 #include <pybind11/stl.h>
 
 namespace mlir {
 namespace python {
 
 // Sets a python error, ready to be thrown to return control back to the