Update travis.yml for Clang, GCC and OS X

Thanks to Hiro Asari on the Travis GitHub for helping with the last of the issues

.travis.yml

@@ -27,22 +27,23 @@ env:
     - BUILD_MODE="asan"
     - BUILD_MODE="ubsan"
     - BUILD_MODE="codecov"
+
 matrix:
   exclude:
     # Skip GCC on OS X entirely
     - os: osx
       compiler: gcc
-
-    # The sanitizer builds run slowly under Clang. CodeCov crashes under Clang.
-    - compiler: clang
-      env: BUILD_MODE="asan"
-    - compiler: clang
-      env: BUILD_MODE="ubsan"
+    # CodeCov crashes under Clang
     - compiler: clang
       env: BUILD_MODE="codecov"
 
+  allow_failures:
+    # Ignore problems with old toolchains
+    - env: BUILD_MODE="ubsan"
+    - env: BUILD_MODE="asan"
+
 script:
-  - make "$BUILD_MODE" && ./cryptest.exe v && ./cryptest.exe tv all
+  - travis_wait make "$BUILD_MODE" && ./cryptest.exe v && ./cryptest.exe tv all
 
 after_success:
   - if [[ ( ("$BUILD_MODE" = "coverage") && ("$CC" = "gcc") ) ]]; then CODECOV_TOKEN="5c7bc59c-e95f-4594-82c3-33e7a1942592" bash <(curl -s https://codecov.io/bash); fi;