[OPENMP] Add support for OMP5 requires directive + unified_address clause

Add support for OMP5.0 requires directive and unified_address clause.
Patches to follow will include support for additional clauses.

Differential Revision: https://reviews.llvm.org/D52359

llvm-svn: 343063
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index ae7f7f3..baf3619 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -1224,6 +1224,10 @@
   void EmitOMPDeclareReduction(const OMPDeclareReductionDecl *D,
                                CodeGenFunction *CGF = nullptr);
 
+  /// Emit a code for requires directive.
+  /// \param D Requires declaration
+  void EmitOMPRequiresDecl(const OMPRequiresDecl *D);
+
   /// Returns whether the given record has hidden LTO visibility and therefore
   /// may participate in (single-module) CFI and whole-program vtable
   /// optimization.