* Added note explaining that view options saved in machine CFG take
precedence over INI/command line.
* Added prerequisites for building HTML documentation under MSYS2 and
Fedora Linux.
* Explicitly mentioned that Ubuntu modifies GCC to enable "fortify
source" by default in the relevant section.
* Removed obsolete reference to glibstdc++6.
* Re-formated compiling guide source (hard wrap at 80 columns,
typographical quotes, code blocks for sample command lines).
-genie.lua: Show GCC ignored attribute warnings, but don't fail for
them.