diff --git a/CMakeLists.txt b/CMakeLists.txt
index 69fc55f..b5a630a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,7 +15,7 @@ find_package(CyrusSASL)
 # include(cmake/FindTarantool.cmake)
 include_directories(${TARANTOOL_INCLUDE_DIRS})
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIC -std=c99")
 
 find_program(GIT git)
 if (EXISTS "${CMAKE_SOURCE_DIR}/.git" AND GIT)