Allow combining `--help -C help -Z help -W help` in one invocation

[jyn514]

Proposal

Current, passing any number of flags after --help acts as if the remaining flags are ignored. For rust-lang/rust#98977, it would be convenient if there were a way to get all help output at once.

I propose that rustc --help -C help be changed to behave the same as rustc --help && rustc -C help to make this easier. Ditto for -Z help and -W help.

I would expect these to be printed in the order they're specified on the command line, rather than in some fixed order.

Mentors or Reviewers

@jyn514

Process

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[rustbot]

Important

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cc @rust-lang/compiler

[Urgau]

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