Use c11 standard See: #1055 (#1056)

Re-enable back C11 as was before

CMakeLists.txt

@@ -3,9 +3,9 @@
 cmake_minimum_required(VERSION 3.5)
 
 project(coturn)
-#set(CMAKE_INCLUDE_CURRENT_DIR ON)
-#set(CMAKE_C_STANDARD 11)
-#set(CMAKE_C_STANDARD_REQUIRED ON)
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_C_STANDARD_REQUIRED ON)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_SOURCE_DIR}/cmake)
 # TODO: Modify this when the version is released