diff --git a/CMakeLists.txt b/CMakeLists.txt
index b26ff8fae5..8f9e56fe18 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,7 +52,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_COMPILER_IS_CLANGXX)
     include(cMake/ConfigureChecks.cmake)
     configure_file(config.h.cmake ${CMAKE_CURRENT_BINARY_DIR}/config.h)
     add_definitions(-DHAVE_CONFIG_H)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-deprecated -Wno-write-strings")
+    set(CMAKE_CXX_FLAGS "-Wall -Wno-deprecated -Wno-write-strings ${CMAKE_CXX_FLAGS}")
     INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR})
     # get linker errors as soon as possible and not at runtime e.g. for modules
     if(UNIX)