apparently macos c++ stdlib is missing c++20 features (particularly
string_view doesn't seem to accept two pointers in a constructor)
and mingw is only present as gcc9 in ubuntu 20.04 (too old)
the user can now define commands '//ivar', '//fvar' and '//svar'
which take identity (which is the variable) as the first argument
followed by any number of user defined arguments with types (one
can use the N argument type to check argument count, and when no
value arguments are provided, print the variable); this allows us
to implement different styles of variable setting without the
interpreter itself knowing about it, as well as ditch all the
stuff with overridden vars and hex vars and whatnot since this is
all specific to the engine and has no place in here
there is still leftover code remaining, which will get cleaned up
afterwards...
Daniel Kolesa