A double is already used in CalcSmoothRatio. Further to this, displays that use TV standard frequencies do not use perfect 60Hz frequencies, but frequencies such as 59.94Hz, 23.976Hz (precisely, 24*(1000/1001) = 23.9760239760239760...) etc.
Reference: 'https://www.ghacks.net/2010/04/28/59-hertz-refresh-rate/', 'http://www.paradiso-design.net/videostandards_en.html'.
# Conflicts:
# source/build/include/baselayer.h
# source/platform/posix/cocoa/i_main.mm