[libclc] [libclc] Declare workitem built-ins in clc, move ptx-nvidiacl workitem built-ins into clc (PR #144333)

[Matt Arsenault via cfe-commits]

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@@ -0,0 +1,22 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include <clc/workitem/clc_get_global_size.h>
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arsenm wrote:

Why are all of these using `#include <>` instead of `#include ""`? Probably should do a bulk fix of these at some point 

https://github.com/llvm/llvm-project/pull/144333