[llvm] [llvm-objcopy] Report unsupported formats before compression (PR #202357)

[James Henderson via llvm-commits]

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jh7370 wrote:

Nit: looks like you've got a spurious additional blank line at the end of the file. Rule of thumb: every file should end in exactly one '\n' character, no more, no less.

https://github.com/llvm/llvm-project/pull/202357