On x86_64, the "core_python_netns" module is installed into ${pyexecdir},
a.k.a. %{python_sitearch}, a.k.a. "/usr/lib64/python2.7/site-packages".
Adding ${pyexecdir} to $PYTHONPATH will prevent the "install" target in
"daemon/src/Makefile" from failing.
Signed-off-by: Gabriel Somlo <glsomlo@cert.org>
properly pass CFLAGS and LDFLAGS when building extension module via setup.py
this fixes Debian build issues when hardening flags are used and properly
passes the -D_GNU_SOURCE required for the "implicit declaration of function
‘posix_openpt’" warning