template simple gtk cmake C on Clion Linux

CMakeLists.txt

cmake_minimum_required(VERSION 3.7)
project(First C) // First -> project name

include(FindPkgConfig)
pkg_check_modules(GTK REQUIRED "gtk+-3.0")

include_directories(${GTK_INCLUDE_DIRS})
link_directories(${GTK3_LIBRARY_DIRS})

add_definitions(${GTK3_CFLAGS_OTHER})
set(CMAKE_CXX_STANDARD 99)

set(SOURCE_FILES main.c)    // main.c -> main file

add_executable(main.c ${SOURCE_FILES})   // main.c -> main file
target_link_libraries(main.c ${GTK3_LIBRARIES} pthread)      // main.c -> main file, pthread -> add thread libraries