diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4bc95329..da80bdbe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -157,7 +157,6 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
     message(STATUS "Detected GCC version 4.7+")
 
     set(NORMAL_CXX_FLAGS "-Wall -Wold-style-cast -pedantic-errors -Wmissing-declarations -lstdc++fs")
-    set(NORMAL_CXX_FLAGS "-Wall -Wold-style-cast -pedantic-errors -Wmissing-declarations")
     set(NORMAL_CXX_FLAGS "${NORMAL_CXX_FLAGS} -Wno-error=deprecated-declarations") # updated version of physfs is not available on some platforms so we keep using deprecated functions, see #958
 
     if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)