If the preprocessor check part is only `__clang__`, CI's such as `Ubuntu-2004-clang` will fail to compile.
This is why we limited the addition to FreeBSD and OpenBSD, which have `clang++` in their base systems.
DragonFly BSD and NetBSD have GCC built into their base systems, so nothing is changed.
- `#include <math.h>` is done in `mruby.h`.
Eliminate the need to worry about the `MRB_NO_FLOAT` macro.
- Include mruby header files before standard header files.
If the standard header file is already placed before `mruby.h`, the standard header file added in the future tends to be placed before `mruby.h`.
This change should some reduce the chances of macros that must be defined becoming undefined in C++ or including problematic header files in a particular mruby build configuration.
Normally a single spell checker can't find all the mistakes or check all types of code.
These mistakes were found by another spell checker inside my editor with a more manual sift / find.
* Use `_Complex` instead of `complex` (MSYS2 do not support `complex`)
* Use `_Dcomplex` instead of `_Complex` on MSCV
* Avoid operator division and multiplication of complex
This gem uses C99 `_Complex` features. You need a C compiler that
supports `_Complex` to enable this gem. All `gcc`, `clang`, `VC` support
`_Complex` so there should not be a big problem.
John Bampton