diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -119,7 +119,11 @@
     set(_varname "HAVE${_varname}")
     check_cxx_compiler_flag("${_flag}" "${_varname}")
     if (${${_varname}})
-        add_compile_options(${_flag})
+        if("${ARGV1}" STREQUAL "CXX_ONLY")
+            set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_flag}" PARENT_SCOPE)
+        else()
+            add_compile_options(${_flag})
+        endif()
     endif()
 endfunction()
 
@@ -135,8 +139,12 @@
     # This warning is triggered by every call to qCDebug()
     add_compile_flag_if_supported(-Wno-gnu-zero-variadic-macro-arguments)
 endif()
-if (CMAKE_COMPILER_CXX_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     add_compile_flag_if_supported(-pedantic)
+    add_compile_flag_if_supported(-Wzero-as-null-pointer-constant CXX_ONLY)
+endif()
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+    add_compile_flag_if_supported(-Wsuggest-override CXX_ONLY)
 endif()
 
 include_directories(${KDevelop_SOURCE_DIR} ${KDevelop_BINARY_DIR})
diff --git a/plugins/astyle/3rdparty/libastyle/CMakeLists.txt b/plugins/astyle/3rdparty/libastyle/CMakeLists.txt
--- a/plugins/astyle/3rdparty/libastyle/CMakeLists.txt
+++ b/plugins/astyle/3rdparty/libastyle/CMakeLists.txt
@@ -7,7 +7,17 @@
 )
 add_library(astylelib STATIC ${astylelib_SRCS})
 set_property(TARGET astylelib PROPERTY POSITION_INDEPENDENT_CODE ON)
+if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "5.0.0")
+      target_compile_options(astylelib PRIVATE "-Wno-zero-as-null-pointer-constant" "-Wno-suggest-override")
+   endif()
+endif()
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     # astyle lib throws lots of warnings with -Wdocumentation
     target_compile_options(astylelib PRIVATE "-Wno-documentation")
+    if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "5.0.0")
+      target_compile_options(astylelib PRIVATE "-Wno-zero-as-null-pointer-constant")
+   endif()
 endif()
+# add as SYSTEM include dir so compiler does not emit warnings for the lib headers
+target_include_directories(astylelib SYSTEM PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/plugins/qmljs/3rdparty/qtcreator-libs/CMakeLists.txt b/plugins/qmljs/3rdparty/qtcreator-libs/CMakeLists.txt
--- a/plugins/qmljs/3rdparty/qtcreator-libs/CMakeLists.txt
+++ b/plugins/qmljs/3rdparty/qtcreator-libs/CMakeLists.txt
@@ -52,15 +52,22 @@
 endif()
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "5.0.0")
+      target_compile_options(kdevqtc-qmlsupport PRIVATE "-Wno-suggest-override" "-Wno-zero-as-null-pointer-constant")
+   endif()
    if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "8.0.0")
       target_compile_options(kdevqtc-qmlsupport PRIVATE "-Wno-class-memaccess")
    endif()
 endif()
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     target_compile_options(kdevqtc-qmlsupport PRIVATE "-Wno-documentation")
+    if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "5.0.0")
+      target_compile_options(kdevqtc-qmlsupport PRIVATE "-Wno-zero-as-null-pointer-constant")
+   endif()
 endif()
 target_compile_definitions(kdevqtc-qmlsupport PUBLIC -DLANGUAGEUTILS_BUILD_DIR -DQTCREATOR_UTILS_LIB -DQT_CREATOR -DQML_BUILD_STATIC_LIB)
-target_include_directories(kdevqtc-qmlsupport PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+# add as SYSTEM include dir so compiler does not emit warnings for the lib headers
+target_include_directories(kdevqtc-qmlsupport SYSTEM PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(kdevqtc-qmlsupport LINK_PRIVATE
     Qt5::Core
     Qt5::Gui