Add support for parallel build in setup.py and use -j2 for Travis CI.

Author: skrah

.travis.yml

@@ -43,10 +43,10 @@ matrix:
       - travis_retry pip install --install-option="--no-cython-compile" Cython==0.24
       - python -c "from __future__ import print_function; import numpy; print(numpy.__version__)"
       - git clone --depth=1 https://github.com/libdynd/libdynd.git
-      - python setup.py install --target=ndt
+      - python setup.py install --target=ndt -j2
       - rm -rf build dist dynd.ndt.egg-info
       - echo dynd.ndt >> requirements.txt
-      - python setup.py install --target=nd
+      - python setup.py install --target=nd -j2
     script:
       - pushd ..
       - python -m dynd.ndt.test

setup.py

@@ -16,8 +16,10 @@
 # need it here already.
 parser = argparse.ArgumentParser()
 parser.add_argument('--target', default='all')
+parser.add_argument('-j', default=None)
 values, rest = parser.parse_known_args()
 DIST_TARGET = values.target
+PARALLEL = values.j
 sys.argv = sys.argv[:1] + rest
 
 #
@@ -210,7 +212,10 @@ def run(self):
     if sys.platform != 'win32':
         cmake_command.append(source)
         self.spawn(cmake_command)
-        self.spawn(['make'])
+        if PARALLEL:
+            self.spawn(['make', '-j%d' % int(PARALLEL)])
+        else:
+            self.spawn(['make'])
     else:
         if "-G" not in self.extra_cmake_args:
             cmake_generator = 'Visual Studio 14 2015'