[3.6] Build docs in parallel (GH-1842) (GH-1872)

(cherry picked from commit eba68e2c42e149acecb15bbeb692786e2540157d)

diff --git a/.travis.yml b/.travis.yml
index fe90bad626ce831f661401b0e2805b3966f651d1..cf524e5549289bc6292499ade888fa55b8542f4b 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -41,7 +41,7 @@ matrix:
         # (Updating the version is fine as long as no warnings are raised by doing so.)
         - python -m pip install sphinx~=1.6.1
       script:
-        - make check suspicious html SPHINXOPTS="-q -W"
+        - make check suspicious html SPHINXOPTS="-q -W -j4"
     - os: linux
       language: c
       compiler: gcc