It seems that setup.py gets deleted before python executes it in
clean-local. To prevent this situation, we just use .NOTPARALLEL.
Previously we distribute nghttp2.c in python, which is cythonized C
source code from nghttp2.pyx. Since it is distributed in archive it
exists in source directory. But we use python distutils which
operates in build directory and does not support C source files in out
of tree directory (i.e., not under the build directory). Copying C
source file to build directory is a bit dirty, so we just decided not
to ship nghttp2.c.
automake version is a bit picky about installation location and uses
different compiler flags from distutils. We prefer official distutils.
Now nghttp2.c, which is generated by cython, is distributed in
archive.
To build extension module, cython is required.
The module is not built with `make` in the top directory.
A user has to run `make build_ext` in python directory.
Currently header compression objects are available for testing.
Tatsuhiro Tsujikawa