Set C standard to C17

CMakeLists.txt

@@ -32,6 +32,9 @@ endif()
 
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
 
+set(CMAKE_C_STANDARD 17)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
@@ -39,7 +42,7 @@ if(MSVC)
   list(APPEND COMPILE_OPTIONS /std:c++17 /MP)
 else()
   list(APPEND COMPILE_OPTIONS
-    $<$<COMPILE_LANGUAGE:C>:-std=c99>
+    $<$<COMPILE_LANGUAGE:C>:-std=c17>
     $<$<COMPILE_LANGUAGE:CXX>:-std=c++17>
     -Wall
     -Wextra