diff --git a/CMakeLists.txt b/CMakeLists.txt
index 548212671b8..c5066a0fdb1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,9 +1,11 @@
-cmake_minimum_required(VERSION 3.5...3.30 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.5...3.20 FATAL_ERROR)
 set(CMAKE_POLICY_VERSION_MINIMUM 3.5 CACHE STRING "")
 list(APPEND CMAKE_TRY_COMPILE_PLATFORM_VARIABLES CMAKE_POLICY_VERSION_MINIMUM)
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS ON)
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
 
 foreach(p
     CMP0025 # CMake 3.0