Try running doxygen

.travis.yml

@@ -12,6 +12,7 @@ before_install:
   - sudo add-apt-repository -y ppa:codegear/release
   - sudo apt-get update -qq
   - sudo apt-get install -y premake4 valgrind
+  - sudo apt-get install doxygen
 
 install: true
 
@@ -27,3 +28,11 @@ script:
   - ./unittest_${config_suffix}
   - valgrind --leak-check=full --error-exitcode=1 ./unittest_${config_suffix}
   - ./perftest_${config_suffix}
+
+after_script:
+  - doxygen build/Doxyfile
+
+matrix:
+  include:
+    - compiler=clang
+      config=release64