One change on the engine side I had to do is undefine our versions of FLT/DBL_MIN/MAX in Scalar.isph because these definition are not available as built-ins and generate warnings if present. That's something we already did for PI before.
#rb daniele.pieroni, tomasz.obrebski
#jira UE-225798
[CL 36824059 by Wojciech Krywult in 5.5 branch]