Pdb file support was changed in CMake 2.8.12, support was added in CMake 3.1.0 to work around the problems created by the change introduced in CMake 2.8.12.
exclude IlmImf/b44ExpLogTable.cpp from the build,
it's used originally to generate IlmImf/b44ExpLogTable.h, but not nessecary for the library.(probably only here for documentation
when included with static linking it introduces a problem with multiple definitions of main()