GCC and Clang's -Wfloat-equal warning notes that comparing floating-point
values with == or != may be questionable. But the few instances of these in
SolveSpace are defensibly correct (as discussed with Jonathan), so to keep
folks from getting nervous that a CAD application isn't handling its floats
correctly, we define an EXACT() macro inside which the -Wfloat-equal
warning is disabled. This macro will also serve as a source-code
annotation, like a comment but better.
(The warning is only disabled for Clang, alas, because GCC is particular
about where _Pragma() can be used. This isn't so bad, however, because the
warning is much easier to enable on Clang [thanks to -Weverything], whereas
with GCC it has to be requested explicitly.)
0afb5618ce