travis-ci/osx: switch to xcode 10.1, since 9.4 is not compatible with gcc-8

Refs: travis-ci/travis-ci#9640

diff --git a/.travis.yml b/.travis.yml
index 946de8a1ef0879424e0f2c6923406b06e411e497..5cf9ed30e4323f64c20eac23b8f0c02c6b51748a 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@ os:
   - osx
 sudo: false
 dist: trusty
+osx_image: xcode10.1
 
 branches:
   except: