The distutils.sysconfig.get_python_inc() function finds headers relative to sys.base_prefix or sys.base_exec_prefix. This causes problems when cross-compiling extension modules because Python's headers are not platform independent.

Instead, get_python_inc() should use the INCLUDEPY and CONFINCLUDEPY variables from sysconfigdata to find headers. The _PYTHON_SYSCONFIGDATA_NAME environment variable can then be used to make build arch Python load sysconfigdata from host arch Python.