[Frontend][OpenMP] introduce OMP.h header file, use it instead of OMP… (llvm#84188)

….h.inc

The consumers of OpenMP-related definitions include a TableGen-generated
file OMP.h.inc. Having a separate OMP.h allows putting additional
declarations in there that are not auto-generated.

This patch is NFC.

Author: kparzysz

flang/lib/Semantics/rewrite-directives.cpp

@@ -11,7 +11,7 @@
 #include "flang/Parser/parse-tree.h"
 #include "flang/Semantics/semantics.h"
 #include "flang/Semantics/symbol.h"
-#include "llvm/Frontend/OpenMP/OMP.h.inc"
+#include "llvm/Frontend/OpenMP/OMP.h"
 #include <list>
 
 namespace Fortran::semantics {

llvm/include/llvm/Frontend/OpenMP/OMP.h

@@ -0,0 +1,18 @@
+//===-- OMP.h - Core OpenMP definitions and declarations ---------- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the core set of OpenMP definitions and declarations.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FRONTEND_OPENMP_OMP_H
+#define LLVM_FRONTEND_OPENMP_OMP_H
+
+#include "llvm/Frontend/OpenMP/OMP.h.inc"
+
+#endif // LLVM_FRONTEND_OPENMP_OMP_H

llvm/include/llvm/Frontend/OpenMP/OMPConstants.h

@@ -15,9 +15,8 @@
 #define LLVM_FRONTEND_OPENMP_OMPCONSTANTS_H
 
 #include "llvm/ADT/BitmaskEnum.h"
-
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Frontend/OpenMP/OMP.h.inc"
+#include "llvm/Frontend/OpenMP/OMP.h"
 
 namespace llvm {
 namespace omp {

llvm/lib/Frontend/OpenMP/OMP.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Frontend/OpenMP/OMP.h.inc"
+#include "llvm/Frontend/OpenMP/OMP.h"
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"