[CMake] Using the FindBoost package

[Edward Diener]

The code is not mine but I am trying to get it to work. On Windows the 
code is calling into the FindBoost.cmake package via a find_package 
call. Before calling find_package the code sets the Boost_INCLUDE_DIR 
and Boost_LIBRARY_DIR to the respective Boost 'boost' and Boost 'libs' 
subdirectories of a Boost installation under Windows. This causes a 
failure because FindBoost looks for the version.h file as 
Boost_INCLUDE_DIR/boost/version.h. This implies that the 
Boost_INCLUDE_DIR ios supposed to be the top-level installation 
directory, but when it is set to that I get errors saying that none of 
the Boost libraries can be found. It seems as if FindBoost.cmake is not 
meant to work on Windows, but only on Linux.

How can I make the call to FindBoost work successfully ?