Travis build to test NO_FILES compilation

This adds a build variant for testing the NO_FILES preprocessor build flag

.travis.yml

@@ -24,9 +24,13 @@ env:
     - CXX_STANDARD=auto
   matrix:
     - BUILD_SHARED=NO
+      NO_FILES=NO
     - BUILD_SHARED=YES
-    - CIVETWEB_SERVE_NO_FILES=NO
-    - CIVETWEB_SERVE_NO_FILES=YES
+      NO_FILES=NO
+    - BUILD_SHARED=NO
+      NO_FILES=YES
+    - BUILD_SHARED=YES
+      NO_FILES=YES
 
 addons:
   apt:
@@ -61,6 +65,7 @@ before_script:
     "-DCIVETWEB_THIRD_PARTY_DIR=${HOME}/third-party"
     -DCIVETWEB_ENABLE_THIRD_PARTY_OUTPUT=YES
     -DCIVETWEB_ENABLE_SSL=${ENABLE_SSL}
+    -DCIVETWEB_SERVE_NO_FILES=${NO_FILES}
     -DCIVETWEB_ENABLE_SSL_DYNAMIC_LOADING=${ENABLE_SSL_DYNAMIC_LOADING}
     -DCIVETWEB_ENABLE_WEBSOCKETS=${ENABLE_WEBSOCKETS}
     -DCIVETWEB_ENABLE_CXX=${ENABLE_CXX}