[Improve] `./build.sh`, `cxx/*` Support all C++98 systems

[SwuduSusuwu]

Issue #3 (Support all C99 systems) is a superset of this.
Issue #19 (Support all C++11 systems) is a subset of this.

This issue is closed once all operating systems (which support C++98) can build + execute this.
Lots to do. If you want this: respond that you wish more resources go to this, or contribute.

[SwuduSusuwu]

?cxx/Macros.hxx: +SUSUWU_DEFAULT, +SUSUWU_FINAL,@420b4a was produced along with the draft of this milestone/issue.
That this issue does not show the commit, shows temporal importance (if you wish for a GitHub issue to show commits which mention that issue, you must first post the issue.)