Compiling 32-bit vs 64-bit project using CMake

You do something along these lines

  if( CMAKE_SIZEOF_VOID_P EQUAL 8 )
    set( BOOST_LIBRARY "/boost/win64/lib" )
  else( CMAKE_SIZEOF_VOID_P EQUAL 8 )
    set( BOOST_LIBRARY "/boost/win32/lib" )
  endif( CMAKE_SIZEOF_VOID_P EQUAL 8 )
  set( CMAKE_EXE_LINKER_FLAGS ${BOOST_LIBRARY} )