Access to PYTHON_VERSION_MAJOR/MINOR

[ax3l]

When including pybind11 directly via add_subdirectory, the selected python interpreter would be useful to be queried, e.g. for install paths.

With find_package(pybind11) the variables PYTHON_VERSION_MAJOR and ..._MINOR leak into the caller's scope and can be queried, but add_subdirectory does proper encapsulation.

Can we maybe add PYTHON_VERSION_MAJOR and PYTHON_VERSION_MINOR as CMake target properties to the pybind11::pybind11 target? With that we could query it from a calling project (or maybe you have an alternative idea as well).

[ax3l]

Ah, found a solution. We can handle it just as PYTHON_INCLUDE_DIRS

[ax3l]

Fix proposed in pybind/pybind11#1434