Most of it is duplicated, hence untested.
Functions like mbrtowc are not exposed by the libc crate, so declare them
ourselves.
Since we don't know the definition of C macros, add two big hacks to make
this work:
1. Replace MB_LEN_MAX and mbstate_t with values (resp types) that should
be large enough for any implementation.
2. Detect the definition of MB_CUR_MAX in the build script. This requires
more changes for each new libc. We could also use this approach for 1.
Additionally, this commit brings a small behavior change to
read_unquoted_escape(): we cannot decode surrogate code points like \UDE01
into a Rust char, so use � (\UFFFD, replacement character) instead.
Previously, we added such code points to a wcstring; looks like they were
ignored when printed.
wchar.rs should not import let alone reexport FFI strings.
Stop re-exporting utf32str! because we use L! instead.
In wchar_ffi.rs, stop re-exporting cxx::CxxWString because that hasn't
seen adoption.
I think we should use re-exports only for aliases like "wstr" or for aliases
into internal modules.
So I'd probably remove `pub use wchar_ffi::wcharz_t = crate::ffi::wcharz_t`
as well.
These will be used in the parser.
Maybe this type should be a struct with boolean fields. The current way has
the upside that the usage is exactly the same as in C++.
Upsizing to `usize` from `i32` doesn't work if `usize` is only 32-bits.
I changed the code to use the `FromStr` impl on `i32`, but we could have also
just used `u64` instead of `i32`.
Also, we should get in the habit of using the appropriate type aliases where
possible (`i32` should be `RawFd`).
