--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -173,7 +173,7 @@ endif()
 if(WANT_DEBUG)
 	set(CMAKE_CXX_FLAGS "$ENV{CMAKE_CXX_FLAGS} -O0")
 else()
-	set(CMAKE_CXX_FLAGS "$ENV{CMAKE_CXX_FLAGS} -O3 -ffast-math")
+	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 endif()
 
 if(WANT_APPIMAGE)