The new Visual C++ 2015 msvcr140.dll run-time changed their math lib.
CCTYPE=MSVC140 LIBC=ucrtd.lib

Now a proper nan/inf string in the math runtime, detected by the MSC_VER
> 18.00.*, i.e. ccversion "19.00.24215.1" for 14.0 (VC++ 2015)

5.6 errors in Perl_deb with invalid use of void expression. Skip that.