rm Doxygen.dirgraphs

(to simplify; 2 flavors are enough)

Doc/Doxygen/CMakeLists.txt

@@ -3,7 +3,7 @@ set(AUTO_DOX_DIR ${CMAKE_BINARY_DIR}/doxygen)
 file(MAKE_DIRECTORY ${AUTO_DOX_DIR})
 file(MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/html)
 add_custom_target(doxy) # this target builds _all_ documentation flavors
-foreach(flavor user long dirgraphs)
+foreach(flavor user long)
     configure_file(Doxyfile.${flavor}.in
         ${AUTO_DOX_DIR}/Doxyfile.${flavor} @ONLY)
     add_custom_target(doxy${flavor}