Support Python built using --exec-prefix
Support Python built using --exec-prefix

Using the sysconfig variable "INCLDIRSTOMAKE" to get header location(s), as they are not necessarily in get_python_inc if Python was configured with a different exec-prefix (because pyconfig.h lives in a separate arch-specific directory)

AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO,AcademySoftwareFoundation/OpenColorIO