POSIX describes WCHAR_MIN and WCHAR_MAX in stdint.h(0P), while
wchar.h(0P) only says "as described in stdint.h".
As there isn't a trivial path of "may make visible", just move it to a
shared header and include it from both files.
The actual value is unchanged, but the previous `0xffffffff` was an
unsigned value, which lead to clang getting mad at `foowc() == WEOF`.
This commit makes it a signed int on clang, which *should* serve
the same purpose and not lead to clang getting mad at us.
The `wcsxfrm` function copies a wide character string into a buffer,
such that comparing the new string against any similarly pre-processed
string with `wcscmp` produces the same result as if the original strings
were compared with `wcscoll`.
Our current `wcscoll` implementation is simply an alias for `wcscmp`, so
`wcsxfrm` needs to perform no actions other than copying the string.
A zero-initialized mbstate_t struct has to be a valid initial state, so
we can just zero-initialize it whenever we need to reset.
Having a helper function for resetting the struct might imply that you
can add additional setup operations afterwards, which is not the case.
POSIX just says that mbstate_t should be an "object type other than an
array type" that can hold the conversion state for converting between
(multi-byte) characters and wide characters.
Since no other information regarding the contents is given, this
apparently means that we should add whatever we need once we start
implementing that conversion.
wint_t is also not supposed to be defined by sys/types.h, but should
be defined in wchar.h instead. Since we require it for our definition of
btowc, let's move it to the correct place.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
