Travis: fix builds on mac os

Author: iMichka

.travis.yml

@@ -126,15 +126,15 @@ matrix:
             - g++-5
     - os: osx
       # BUILD 14 ------------------
-      osx_image: xcode7.3
+      osx_image: xcode9.4
       language: generic
       env:
         - XML_GENERATOR="castxml"
         - TRAVIS_PYTHON_VERSION="2"
         - SITECUSTOMIZELIBPATH="/usr/local/lib/python2.7/site-packages/sitecustomize.py"
     - os: osx
       # BUILD 15 ------------------
-      osx_image: xcode7.3
+      osx_image: xcode9.4
       language: generic
       env:
         - XML_GENERATOR="castxml"
@@ -157,8 +157,9 @@ matrix:
 
 before_install:
   # OS X
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then travis_retry brew update; fi
-  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ $TRAVIS_PYTHON_VERSION == 3 ]]; then brew install python3; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then travis_retry brew update && brew upgrade; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ $TRAVIS_PYTHON_VERSION == 2 ]]; then brew install python@2; fi
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ $TRAVIS_PYTHON_VERSION == 3 ]]; then brew install python; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ $TRAVIS_PYTHON_VERSION == 3 ]]; then sudo ln -sf /usr/local/bin/pip3 /usr/local/bin/pip; fi
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]] && [[ $TRAVIS_PYTHON_VERSION == 3 ]]; then sudo ln -sf /usr/local/bin/python3 /usr/local/bin/python; fi