Exclude SFML from the All target, and flag as a system library, closes #6

Author: JonnyPtn

CMakeLists.txt

@@ -1,14 +1,16 @@
-cmake_minimum_required(VERSION 3.16)
+cmake_minimum_required(VERSION 3.28)
 project(CMakeSFMLProject LANGUAGES CXX)
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 option(BUILD_SHARED_LIBS "Build shared libraries" OFF)
 
 include(FetchContent)
-FetchContent_Declare(SFML
+FetchContent_Declare(sfml
     GIT_REPOSITORY https://github.com/SFML/SFML.git
-    GIT_TAG 2.6.x)
-FetchContent_MakeAvailable(SFML)
+    GIT_TAG 2.6.x
+    EXCLUDE_FROM_ALL
+    SYSTEM)
+FetchContent_MakeAvailable(sfml)
 
 add_executable(CMakeSFMLProject src/main.cpp)
 target_link_libraries(CMakeSFMLProject PRIVATE sfml-graphics)