* Remove namespaces
* Prefer `bool operator==`, not `friend auto operator==`
* Prefer not to use `using`
* Use a `constexpr` function instead of a template for `flipTable`
- Since we have style rules to include foo.hpp at the top of its
corresponding foo.cpp, this takes any headers included by foo.hpp
as being also guaranteed for foo.cpp.
- Use C-style <foo.h> instead of <cfoo>, since the latter only
guarantees putting symbols in the `std` namespace, which we are
not using for C functions (e.g. `printf` not `std::printf`).
- Remove now-unused `__PRETTY_FUNCTION__` reporting
* Fixes from temporarily re-enabling more compiler warnings
* More edits suggested by cppcheck
* Fix hanging on append_yylval_string
* Fix FOR loop increment
- Changes most `/* comments */` to `// comments`
- Changes `/**` block comments consistently to `/*`
- Adds consistent license comments to all files
Also renames `T_POP_SET` to `T_Z80_SET`
