knumber_float fix MSVC 2022 compiler issues with log2 and exp2
Fix MSVC 2022 compiler issue "C:_\58afbb54\kcalc\knumber\knumber_float.cpp(15):
error C2169: 'log2': intrinsic function, cannot be defined
C:_\58afbb54\kcalc\knumber\knumber_float.cpp(19): warning C4273:
'exp2': inconsistent dll linkage
C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\ucrt\corecrt_math.h(506):
note: see previous definition of 'exp2'".
Edited by Raresh Rus