diff --git a/RepositoryExternal.mk b/RepositoryExternal.mk
index b039484338a8..6b0c69b3c804 100644
--- a/RepositoryExternal.mk
+++ b/RepositoryExternal.mk
@@ -3084,7 +3084,7 @@ $(call gb_LinkTarget_set_include,$(1),\
 	$$(INCLUDE) \
 )
 
-$(call gb_LinkTarget_add_defs,$(1),\
+$(call gb_LinkTarget_add_cxxflags,$(1),\
 	$(filter-out -I% -isystem%,$(subst -isystem /,-isystem/,$(KF5_CFLAGS))) \
 )
 
diff --git a/vcl/Executable_lo_kde5filepicker.mk b/vcl/Executable_lo_kde5filepicker.mk
index f3e940953601..a34682966778 100644
--- a/vcl/Executable_lo_kde5filepicker.mk
+++ b/vcl/Executable_lo_kde5filepicker.mk
@@ -29,6 +29,9 @@ $(eval $(call gb_Executable_set_include,lo_kde5filepicker,\
 $(eval $(call gb_Executable_add_cxxflags,lo_kde5filepicker,\
     $$(INCLUDE) \
     $$(BOOST_CXXFLAGS) \
+    $(QT5_CFLAGS) \
+    $(QT5_GLIB_CFLAGS) \
+    $(KF5_CFLAGS) \
 ))
 
 $(eval $(call gb_Executable_use_custom_headers,lo_kde5filepicker,\
@@ -69,11 +72,6 @@ $(eval $(call gb_Executable_use_externals,lo_kde5filepicker,\
 	dbus \
 ))
 
-$(eval $(call gb_Executable_add_defs,lo_kde5filepicker,\
-    $(QT5_CFLAGS) \
-    $(QT5_GLIB_CFLAGS) \
-    $(KF5_CFLAGS) \
-))
 $(eval $(call gb_Executable_add_libs,lo_kde5filepicker,\
     $(QT5_LIBS) \
     $(QT5_GLIB_LIBS) \
diff --git a/vcl/Library_vclplug_gtk3_kde5.mk b/vcl/Library_vclplug_gtk3_kde5.mk
index 089d6ee31a1f..cfd370221dde 100644
--- a/vcl/Library_vclplug_gtk3_kde5.mk
+++ b/vcl/Library_vclplug_gtk3_kde5.mk
@@ -35,11 +35,11 @@ $(eval $(call gb_Library_set_include,vclplug_gtk3_kde5,\
 $(eval $(call gb_Library_add_cxxflags,vclplug_gtk3_kde5,\
     $$(INCLUDE) \
     $$(GTK3_CFLAGS) \
+    $(KF5_CFLAGS) \
 ))
 
 $(eval $(call gb_Library_add_defs,vclplug_gtk3_kde5,\
     -DVCLPLUG_GTK_IMPLEMENTATION -DVCLPLUG_GTK3_KDE5_IMPLEMENTATION \
-    $(KF5_CFLAGS) \
 ))
 
 $(eval $(call gb_Library_use_custom_headers,vclplug_gtk3_kde5,\
diff --git a/vcl/Library_vclplug_kde5.mk b/vcl/Library_vclplug_kde5.mk
index d097845bd5ce..181a318ab797 100644
--- a/vcl/Library_vclplug_kde5.mk
+++ b/vcl/Library_vclplug_kde5.mk
@@ -62,7 +62,7 @@ $(eval $(call gb_Library_use_externals,vclplug_kde5,\
 ))
 
 ifneq ($(QT5_HAVE_GLIB),)
-$(eval $(call gb_Library_add_defs,vclplug_kde5,\
+$(eval $(call gb_Library_add_cxxflags,vclplug_kde5,\
     $(QT5_GLIB_CFLAGS) \
 ))
 
@@ -71,7 +71,7 @@ $(eval $(call gb_Library_add_libs,vclplug_kde5,\
 ))
 endif
 
-$(eval $(call gb_Library_add_defs,vclplug_kde5,\
+$(eval $(call gb_Library_add_cxxflags,vclplug_kde5,\
     $(KF5_CFLAGS) \
 ))
 $(eval $(call gb_Library_add_libs,vclplug_kde5,\
diff --git a/vcl/Library_vclplug_qt5.mk b/vcl/Library_vclplug_qt5.mk
index 3231672c8743..543a4569ceb9 100644
--- a/vcl/Library_vclplug_qt5.mk
+++ b/vcl/Library_vclplug_qt5.mk
@@ -63,7 +63,7 @@ $(eval $(call gb_Library_use_externals,vclplug_qt5,\
     qt5 \
 ))
 
-$(eval $(call gb_Library_add_defs,vclplug_qt5,\
+$(eval $(call gb_Library_add_cxxflags,vclplug_qt5,\
     $(QT5_CFLAGS) \
 ))
 $(eval $(call gb_Library_add_libs,vclplug_qt5,\
@@ -71,7 +71,7 @@ $(eval $(call gb_Library_add_libs,vclplug_qt5,\
 ))
 
 ifneq ($(QT5_HAVE_GLIB),)
-$(eval $(call gb_Library_add_defs,vclplug_qt5,\
+$(eval $(call gb_Library_add_cxxflags,vclplug_qt5,\
     $(QT5_GLIB_CFLAGS) \
 ))
 $(eval $(call gb_Library_add_libs,vclplug_qt5,\