[utils][TableGen] Implement clause aliases as alternative spellings (#141765)

Use the spellings in the generated clause parser. The functions
`get<lang>ClauseKind` and `get<lang>ClauseName` are not yet updated.

The definitions of both clauses and directives now take a list of
"Spelling"s instead of a single string. For example
```
def ACCC_Copyin : Clause<[Spelling<"copyin">,
                          Spelling<"present_or_copyin">,
                          Spelling<"pcopyin">]> { ... }
```

A "Spelling" is a versioned string, defaulting to "all versions".

For background information see

https://discourse.llvm.org/t/rfc-alternative-spellings-of-openmp-directives/85507

0 files changed, 0 insertions, 0 deletions