05d8b565ad1a1d6c0c1e93dc47f1d828043fcafc deduplicated wasi-libc headers
that are identical to upstream musl, but because some public headers
match the same `#include <>` patterns as private headers, this resulted
in unmodified upstream musl headers sometimes getting prioritized when
compiling wasi-libc, resulting in incorrect definitions. For example,
`UTIME_OMIT` is supposed to be -2 on WASI, but became 0x3ffffffe.

The restored headers were sourced from
<https://github.com/WebAssembly/wasi-libc/tree/c89896107d7b57aef69dcadede47409ee4f702ee>
which is the same revision as the most recent wasi-libc sync
07cc32b0041e5e12f72d682fd06a995fe904d556.