forget to add linux clang cmake

.travis.yml

@@ -12,6 +12,19 @@ matrix:
       script:
         cmake -GNinja .. && cmake --build .
 
+    - os: linux
+      dist: bionic
+      compiler:
+        - clang
+      addons:
+        apt:
+          packages:
+            - libusb-dev
+            - doxygen
+            - cmake
+      script:
+        - mkdir build && cd build && cmake -DCMAKE_INSTALL_PREFIX=~/.local .. && make -j2 && make install
+        
     - os: linux
       dist: bionic
       compiler: