[llvm] [Offload] Use new error code handling mechanism (PR #139275)

[Ross Brunton via llvm-commits]

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+//===- Auto-generated file, part of the LLVM/Offload project --------------===//
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RossBrunton wrote:

We have a target `OffloadGenerate` which generates both liboffload sources and the OffloadErrcodes.inc file, which is not run as part of the build. If OffloadErrcodes.inc was generated as part of the build, then any changes to the tablegen file could result in the offload sources getting out of sync with the manually run OffloadGenerate.

In effect, doing it as part of OffloadGenerate forces tablegen changes to be synchronised to both the inc files and liboffload.

As for why `OffloadGenerate` isn't ran as part of the build, @callumfare can probably explain the reasoning better than I can.

https://github.com/llvm/llvm-project/pull/139275