diff --git a/CMakeLists.txt b/CMakeLists.txt
index bf4fe49b2..cf115b3d1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.1.0)
 
 project(sway C)
 
-set(CMAKE_C_FLAGS "-g")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g")
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_EXTENSIONS OFF)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)