Fix Flang build after addition of a new OpenMP clauses for a clang patch (D76342).
Flang is using TableGen to generation the declaration of clause checks and the new clause
was missing a definiton.
Reviewed By: klausler
Differential Revision: https://reviews.llvm.org/D96808
CHECK_SIMPLE_CLAUSE(Relaxed, OMPC_relaxed)
CHECK_SIMPLE_CLAUSE(SeqCst, OMPC_seq_cst)
CHECK_SIMPLE_CLAUSE(Simd, OMPC_simd)
+CHECK_SIMPLE_CLAUSE(Sizes, OMPC_sizes)
CHECK_SIMPLE_CLAUSE(TaskReduction, OMPC_task_reduction)
CHECK_SIMPLE_CLAUSE(To, OMPC_to)
CHECK_SIMPLE_CLAUSE(UnifiedAddress, OMPC_unified_address)