Using the real target "real" type (cross compiling)

[Dan Olson]

I switched to using ldc merge-2.064 branch for all my iOS hacking. The
newer std.math has some nice static asserts that failed because dmd is
using the compile host "long double" type for determing the properties
of type real.  Thank you for static assertions!

Mac x86_64 long double != Arm long double

I hacked dmd to make longdouble = double so I could cross compile this
newer phobos to iOS.  But are there other things like real types that
dmd code is learning from host, but should be told what the target is
using?

Anyway, this seems like more of a dmd thing.  What is the best approach
to solve?  I am ok for now with hacking on my own branch but wishing for
a better solution.

Thanks,
-- 
Dan