To fix bogus MSVC warnings:

  c:\projects\harfbuzz\src\hb-array.hh(189): warning C4521: 'hb_array_t<Type>': multiple copy constructors specified [C:\projects\harfbuzz\build\harfbuzz.vcxproj]
  c:\projects\harfbuzz\src\hb-array.hh(189): warning C4522: 'hb_array_t<Type>': multiple assignment operators specified [C:\projects\harfbuzz\build\harfbuzz.vcxproj]