Refactor C FFI variadics to more closely match their C counterparts, and add Clone implementation#59625

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bors merged 1 commit intorust-lang:masterfrom

immunant:copy_variadics_typealias

Jun 19, 2019

Commits on Jun 17, 2019

Expose `VaListImpl` as the Rust equivalent of `__va_list_tag` and implement Clone for it.
ahomescu
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