* Explicitly check for availbility of std::byte
GCC > 7.3 defines __cpp_lib_byte >= 201603 when std::byte is available.
On libc++ std::byte is available since version 5.0. This can be checked
with _LIBCPP_VERSION >= 5000.
This fixes 713.
* Add missing \ in preprocessor check
C++17 defines `std::byte*` to have the same aliasing properties as
`char*`. Hence, we mark it with the `__may_alias__` attribute under gcc
and clang.
Based on the fix by Martin Moene in byte-lite.
Fixes#663
Project files were not following the clang-format style. For people
using IDEs were clang-format is always run after a save this would
cause unwanted changes.
This commit only applies "clang-format -i" to files.
* Nest "gsl" directory inside a new "include" directory.
* Cleanup the _MSC_VER conditionals a bit; use constexpr on VS2017+.
* Don't #define noexcept on non-Microsoft implementations.
* Workaround VS2017 bug in multi_span. (Also implement == and != for static_bounds_dynamic_range_t because I'm an EoP semantic soundness snob.)
Fixes#441.
