[llvm] [SYCL] Add libsycl, a SYCL RT library implementation project (PR #144372)

[Alexey Bader via llvm-commits]

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@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of the Platform class, which encapsulates
+/// a single SYCL platform on which kernel functions may be executed.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBSYCL_PLATFORM_HPP
+#define _LIBSYCL_PLATFORM_HPP
+
+#include <sycl/__detail/config.hpp>
+
+_LIBSYCL_BEGIN_NAMESPACE_SYCL
+
+class _LIBSYCL_EXPORT platform {
+public:
+  /// Constructs a SYCL platform using the default device.
----------------
bader wrote:

```suggestion
  /// Constructs a SYCL platform which contains the default device.
```

https://github.com/llvm/llvm-project/pull/144372