[Todo] wrap C++-specific protocols with neutral macros

[SwuduSusuwu]

Rationales

Discussion (with poll to vote on alternative solutions).

Background

https://github.com/SwuduSusuwu/SusuLib/blob/preview/cxx/Macros.hxx has numerous such macros, but due to the problems (listed above), limited those to just use on structures which already have to use macros:

• SUSUWU_PREFER_C (if preference is C; #define SUSUWU_PREFER_C true. If not; #define SUSUWU_PREFER_C false.)
• SUSUWU_IF_CPLUSPLUS(TRUE, FALSE) (if __cplusplus; #define SUSUWU_IF_CPLUSPLUS(TRUE, FALSE) TRUE. If not; #define SUSUWU_IF_CPLUSPLUS(TRUE, FALSE) FALSE.)
• SUSUWU_PRINT

Due to the discussion's mentioned disadvantages, have not used macros such as the SUSUWU_CAST macro above.
Related to this:

• classSysArgs detects compiler support to choose C-style arrays versus std::span