Do not check the system clock on r-devel (#3179)

yutannihilation · web-flow · commit eef361ae81a6 · 2019-03-07T21:11:26.000+09:00
diff --git a/.travis.yml b/.travis.yml
@@ -7,6 +7,8 @@ dist: trusty
 matrix:
   include:
   - r: devel
+    # avoind errors due to world clock API (hopefully can be removed in future)
+    env: _R_CHECK_SYSTEM_CLOCK_=false
   - r: release
     env: VDIFFR_RUN_TESTS=true
     before_cache:
