Travis ASan: Use default Travis clang (v5.0)

.travis.yml

@@ -33,15 +33,10 @@ matrix:
           packages:
             - g++-5
     - os: linux
-      compiler: clang++-3.7
-      env: AUTOTOOLS=no COVERAGE=no BUILD=static
-      addons:
-        apt:
-          sources:
-            - ubuntu-toolchain-r-test
-            - llvm-toolchain-precise-3.7
-          packages:
-            - clang-3.7
+      compiler: clang
+      # This build runs with ASan and we set `detect_odr_violation=0`
+      # to work around https://bugs.llvm.org/show_bug.cgi?id=37545.
+      env: AUTOTOOLS=no COVERAGE=no BUILD=static ASAN_OPTIONS=detect_odr_violation=0
     - os: linux
       compiler: clang
       env: AUTOTOOLS=yes COVERAGE=no BUILD=shared