diff --git a/core/libs/facesengine/CMakeLists.txt b/core/libs/facesengine/CMakeLists.txt
index 281c35af4e..d5ad70b0f1 100644
--- a/core/libs/facesengine/CMakeLists.txt
+++ b/core/libs/facesengine/CMakeLists.txt
@@ -1,123 +1,127 @@
 #
 # Copyright (c) 2010-2019, Gilles Caulier, <caulier dot gilles at gmail dot com>
 #
 # Redistribution and use is allowed according to the terms of the BSD license.
 # For details see the accompanying COPYING-CMAKE-SCRIPTS file.
 
 kde_enable_exceptions()
 
 include_directories($<TARGET_PROPERTY:Qt5::Xml,INTERFACE_INCLUDE_DIRECTORIES>
                     $<TARGET_PROPERTY:Qt5::Sql,INTERFACE_INCLUDE_DIRECTORIES>
                     $<TARGET_PROPERTY:Qt5::Gui,INTERFACE_INCLUDE_DIRECTORIES>
                     $<TARGET_PROPERTY:Qt5::Core,INTERFACE_INCLUDE_DIRECTORIES>
                     $<TARGET_PROPERTY:Qt5::Widgets,INTERFACE_INCLUDE_DIRECTORIES>
                     $<TARGET_PROPERTY:Qt5::Concurrent,INTERFACE_INCLUDE_DIRECTORIES>
 
                     $<TARGET_PROPERTY:KF5::ConfigCore,INTERFACE_INCLUDE_DIRECTORIES>
                     $<TARGET_PROPERTY:KF5::I18n,INTERFACE_INCLUDE_DIRECTORIES>
 )
 
 include_directories(${CMAKE_CURRENT_BINARY_DIR}/..
                     ${CMAKE_CURRENT_SOURCE_DIR}/facedb
                     ${CMAKE_CURRENT_SOURCE_DIR}/detection
                     ${CMAKE_CURRENT_SOURCE_DIR}/detection/opencv3-face
                     ${CMAKE_CURRENT_SOURCE_DIR}/recognition/opencv-lbph
                     ${CMAKE_CURRENT_SOURCE_DIR}/recognition/opencv-eigenfaces
                     ${CMAKE_CURRENT_SOURCE_DIR}/recognition/opencv-fisherfaces
                     ${CMAKE_CURRENT_SOURCE_DIR}/alignment/congealing
                     ${CMAKE_CURRENT_SOURCE_DIR}/preprocessing/shape-predictor
 
 #                   ${CMAKE_CURRENT_SOURCE_DIR}/alignment/flandmark
 #                   ${CMAKE_CURRENT_SOURCE_DIR}/preprocessing/tantriggs
 )
 
 if(ENABLE_FACESENGINE_DNN)
     include_directories(${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn/dnnface/dnn_base
                         ${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn/dnnface/image_processing
                         ${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn/dnnface/image_transforms
                         ${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn/dnnface/matrix
                         ${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn/dnnface/nn
                         ${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn/dnnface
                         ${CMAKE_CURRENT_SOURCE_DIR}/recognition/dlib-dnn
     )
 endif()
 
 set(facesengine_LIB_SRCS detection/opencvfacedetector.cpp
                          preprocessing/shape-predictor/fullobjectdetection.cpp
                          preprocessing/shape-predictor/qdatastreamoverloads.cpp
                          facedetector.cpp
                          identity.cpp
                          dataproviders.cpp
 
                          detection/opencv3-face/facerec.cpp
                          detection/opencv3-face/lbph_faces.cpp
                          detection/opencv3-face/eigen_faces.cpp
                          detection/opencv3-face/fisher_faces.cpp
                          detection/opencv3-face/predict_collector.cpp
 
 #                        alignment/flandmark/flandmarkaligner.cpp
 #                        preprocessing/tantriggs/tantriggspreprocessor.cpp
 )
 
 set(facesengine_database_LIB_SRCS recognitiondatabase.cpp
                                   simpletrainingdataprovider.cpp
 
                                   # Eigen Faces recognition module based on OpenCV
                                   recognition/opencv-eigenfaces/eigenfacemodel.cpp
                                   recognition/opencv-eigenfaces/opencveigenfacerecognizer.cpp
                                   recognition/opencv-eigenfaces/facerec_eigenborrowed.cpp
 
                                   # Fisher Faces recognition module based on OpenCV
                                   recognition/opencv-fisherfaces/fisherfacemodel.cpp
                                   recognition/opencv-fisherfaces/opencvfisherfacerecognizer.cpp
                                   recognition/opencv-fisherfaces/facerec_fisherborrowed.cpp
 
 
                                   # Lpbh Faces recognition module based on OpenCV
                                   recognition/opencv-lbph/lbphfacemodel.cpp
                                   recognition/opencv-lbph/opencvlbphfacerecognizer.cpp
                                   recognition/opencv-lbph/opencvmatdata.cpp
                                   recognition/opencv-lbph/facerec_borrowed.cpp
 
                                   alignment/congealing/funnelreal.cpp
 
                                   facedb/facedbaccess.cpp
                                   facedb/facedbbackend.cpp
                                   facedb/facedboperationgroup.cpp
                                   facedb/facedbschemaupdater.cpp
                                   facedb/facedb.cpp
 )
 
 if(ENABLE_FACESENGINE_DNN)
 
     if(NOT MSVC)
 
         # Dlib DNN generate plenty of wrong warnings. Remove these workaround later when code will be ported to OpenCV DNN.
-        REMOVE_GCC_COMPILER_WARNINGS("-Wcast-align")
         REMOVE_GCC_COMPILER_WARNINGS("-Wextra")
         REMOVE_GCC_COMPILER_WARNINGS("-Wundef")
         REMOVE_GCC_COMPILER_WARNINGS("-Wall")
 
+        DISABLE_CLANG_COMPILER_WARNINGS("4.99.99" "-Wno-cast-align")
+        DISABLE_CLANG_COMPILER_WARNINGS("4.99.99" "-Wno-sign-compare")
+        DISABLE_CLANG_COMPILER_WARNINGS("4.99.99" "-Wno-unused-parameter")
+        DISABLE_CLANG_COMPILER_WARNINGS("4.99.99" "-Wno-unused-variable")
+
     endif()
 
     set(facesengine_database_LIB_SRCS ${facesengine_database_LIB_SRCS}
                                       # Neural NetWork Faces recognition module based on Dlib
                                       recognition/dlib-dnn/dnnfacemodel.cpp
                                       recognition/dlib-dnn/opencvdnnfacerecognizer.cpp
                                       recognition/dlib-dnn/facerec_dnnborrowed.cpp
     )
 endif()
 
 add_library(digikamfacesengine_src
             OBJECT
             ${facesengine_LIB_SRCS}
 )
 
 add_library(digikamfacesengine STATIC $<TARGET_OBJECTS:digikamfacesengine_src>)
 
 add_library(digikamfacesenginedatabase_src
             OBJECT
             ${facesengine_database_LIB_SRCS}
 )
 
 add_library(digikamfacesenginedatabase STATIC $<TARGET_OBJECTS:digikamfacesenginedatabase_src>)