Since https://reviews.llvm.org/D131441, libc++ must be included before
LibC. As clang includes libc++ as one of the system includes, LibC
must be included after those, and the only correct way to do that is
to install LibC's headers into the sysroot.
Targets that don't link with LibC yet require its headers for one
reason or another must add install_libc_headers as a dependency to
ensure that the correct headers have been (re)installed into the
sysroot.
LibC/stddef.h has been dropped since the built-in stddef.h receives
a higher include priority.
In addition, string.h and wchar.h must
define __CORRECT_ISO_CPP_STRING_H_PROTO and
_LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS respectively in order to tell
libc++ to not try to define methods implemented by LibC.
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 *
