Add NO_PY_EXT environment variable to disable compilation of the C module, which is not working very well in cross-compile mode.
Add NO_PY_EXT environment variable to disable compilation of
the C module, which is not working very well in cross-compile
mode.

sobomax/libelperiodic,sobomax/libelperiodic,sobomax/libelperiodic,sobomax/libelperiodic