diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3fa5fde..c115b6e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -44,7 +44,7 @@ if (MARIADB_FOUND AND NOT MARIADB_SSL AND WITH_SSL)
     set(WITH_SSL OFF)
 endif()
 
-set(CMAKE_C_FLAGS "-std=gnu99 -Wall -Wno-deprecated-declarations -Wunused -Wwrite-strings -Wno-strict-aliasing -Wextra -Wshadow -g -Werror ${MYSQL_CFLAGS}")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu99 -Wall -Wno-deprecated-declarations -Wunused -Wwrite-strings -Wno-strict-aliasing -Wextra -Wshadow -g -Werror ${MYSQL_CFLAGS}")
 include_directories(${MYDUMPER_SOURCE_DIR} ${MYSQL_INCLUDE_DIR} ${GLIB2_INCLUDE_DIR} ${PCRE2_INCLUDE_DIR} ${ZLIB_INCLUDE_DIRS} )
 
 OPTION(WITH_ASAN "Build with ASAN" OFF)