BUILD: -Wno-unknown-warning-option for clang

CMakeLists.txt

@@ -140,6 +140,10 @@ if (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
         -Wno-padded
         -Wno-global-constructors
         -Wno-exit-time-destructors
+
+        # Don't triger warnings about not known warnings all the time...
+        # (because of the different clang versions)
+        -Wno-unknown-warning-option
     )
     target_link_libraries(Vivy PRIVATE
         -fopenmp