diff --git a/CMakeLists.txt b/CMakeLists.txt
index 599ca6b256..c30b679eb9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -84,6 +84,7 @@ ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_METHODS -Wsug
 ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wsuggest-override)
 ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_DUPLICATED_COND -Wduplicated-cond)
 ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_NON_VIRTUAL_DTOR -Wnon-virtual-dtor)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_MISSING_VARIABLE_DECLARATIONS -Wmissing-variable-declarations)
 if (MINGW)
     ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wno-error=redundant-decls)
 endif ()