This change results out of necessity since the Nintendo Switch console
SDK does not support `std::filesystem`. The SDK still provides the
`<filesystem>` header, but with an `#error` directive, effectively
breaking any build that includes `<filesystem>`
Because `<filesystem>` is present, `FMT_HAS_INCLUDE` is insufficient
here. With this change and `FMT_CPP_LIB_FILESYSTEM` in place, one can
define `FMT_CPP_LIB_FILESYSTEM=0` to work around this issue.
This assumes that `<filesystem>` can be included (without warnings) if
`FMT_CPP_LIB_FILESYSTEM` is set. If this is not the case, fmt would be
broken even before this change as `std::filesystem::path` is used
without the accompanying header.
Fixes#4207.
LLVM Clang on Windows does not define `__GNUC__`. The preprocessor falls
to `#elif FMT_MSC_VERSION && !_HAS_EXCEPTIONS` with `_HAS_EXCEPTIONS 1`
defined in vcruntime.h:104.
Changing type data_ to size_t because
1. If lib is cross-compiled for win32 using MXE environment it cause
compilation warning -Wconversion on line 730 as sizeof(unsigned long)
= 4 and sizeof(size_t) = 8
2. When lib is compiled on Unix like compiler generate warning
-Wuseless-cast if static_cast is used to fix issue in 1
Fixes warning reported by top of trunk Clang:
include/fmt/chrono.h:447:36: error: function 'throw_duration_error' could be declared with attribute 'noreturn'
* Conform `std::iterator_traits<fmt::appender>` to [iterator.traits]/1
> In addition, the types
> ```c++
> iterator_traits<I>::pointer
> iterator_traits<I>::reference
> ```
> shall be defined as the iterator’s pointer and reference types; that is, for an iterator object `a` of class type, the same type as `decltype(a.operator->())` and `decltype(*a)`, respectively. The type `iterator_traits<I>::pointer` shall be void for an iterator of class type `I` that does not support `operator->`. Additionally, in the case of an output iterator, the types
> ```c++
> iterator_traits<I>::value_type
> iterator_traits<I>::difference_type
> iterator_traits<I>::reference
> ```
> may be defined as `void`.
* Remove unnecessary member types from basic_appender
This reverts commit 1accf6c0a0.
* Address clang-format issue
