This shouldn't change behavior (or even object code) at all because
those assignments are all without effect. Removing that code removes
noise which helps working with code analysis tools.
Previously we would fail in some parts of the code if we did not have a
premade configuration, now we use any code that was marked as Linux, BSD and
Solaris as our basis in order to support building unknown Unix systems.
Mostly missing headers, explicit parentheses and new prototypes.
Some Caveats:
* I haven't compile-tested the SVR4 getpty file, it might need another tweak
* There were operator precedence bugs in TermPrimCursor.c and TermPrimRender.c
(^ vs. !=). This might change behaviour, but at least I haven't experienced
any crashes ...
* This adds a little more dependencies for include ordering, but unless we
want to play the "headers that include headers that include headers..." game,
this is unavoidable.