[clang] [CIR] Upstream simple function bodies (PR #127674)

[Henrich Lauko via cfe-commits]

================
@@ -0,0 +1,134 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Internal per-function state used for AST-to-ClangIR code gen
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_CIR_CODEGEN_CIRGENFUNCTION_H
+#define LLVM_CLANG_LIB_CIR_CODEGEN_CIRGENFUNCTION_H
----------------
xlauko wrote:

```suggestion
#define CLANG_LIB_CIR_CODEGEN_CIRGENFUNCTION_H
```

https://github.com/llvm/llvm-project/pull/127674