try more JOBS=10 on osx

.travis.yml

@@ -45,11 +45,11 @@ matrix:
       compiler: clang
       # https://docs.travis-ci.com/user/languages/objective-c/#Supported-OS-X-iOS-SDK-versions
       osx_image: xcode7.2 # upgrades clang from 6 -> 7
-      env: JOBS=8 MASON_PUBLISH=true
+      env: JOBS=10 MASON_PUBLISH=true
     - os: osx
       compiler: clang
       osx_image: xcode7.2 # upgrades clang from 6 -> 7
-      env: JOBS=8 COVERAGE=true
+      env: JOBS=10 COVERAGE=true
 
 before_install:
  - export PYTHONUSERBASE=${PYTHONUSERBASE}