slaprunner: Build NumPy & friends in parallel

Starting from NumPy 1.10 numpy's distutils support parallel building

    http://docs.scipy.org/doc/numpy/user/install.html#basic-installation
    https://github.com/numpy/numpy/commit/23d54617

and this way software which uses numpy's distutils (scipy,
scikit-learn, etc) should support it too.

Let's use it, like we currently already use MAKEFLAGS for speeding up
make-based projects.

/cc @jerome, @cedric.leninivin, @kazuhiko

software/slaprunner/common.cfg

@@ -156,7 +156,7 @@ mode = 0644
 [template-supervisord]
 recipe = hexagonit.recipe.download
 url = ${:_profile_base_location_}/template/${:filename}
-md5sum = ca93b052aea55208d167b46f91c50f32
+md5sum = 9000773130409a566e36ad88f436c4de
 location = ${buildout:parts-directory}/${:_buildout_section_name_}
 filename = supervisord.conf.in
 download-only = true

software/slaprunner/template/supervisord.conf.in

@@ -28,7 +28,7 @@ stderr_logfile = {{ supervisord['no_logfile'] }}
 directory = {{ supervisord['directory'] }}
 {# how many parallel build jobs to spawn when compiling software -#}
 {% set njobs = builtin.max(1, (multiprocessing.cpu_count() // builtin.int(slapparameter_dict.get('cpu-usage-ratio', 4)))) -%}
-environment = PATH="{{- supervisord['path'] -}}",MAKEFLAGS="-j{{ njobs }}"
+environment = PATH="{{- supervisord['path'] -}}",MAKEFLAGS="-j{{ njobs }}",NPY_NUM_BUILD_JOBS="{{ njobs }}"
 
 [program:{{- supervisord['slapgrid-cp'] -}}]
 command = {{ supervisord['slapgrid-cp-command'] }}