Add CMake file for LINUX/WINDOWS compatibility

Due to developers working on windows and linux the compilation process
should be compatible thus using CMAKE.

Tested this configuration on both systems, currently works well and
finds the SDL2 library when installed.

CMakeLists.txt

@@ -0,0 +1,46 @@
+cmake_minimum_required(VERSION 3.7)
+
+project(Snake)
+
+
+#--- SDL2 location on Windows ---
+if(WIN32)
+    # Specify downloaded SDL2 library folder location
+    set(SDL2_FOLDER "${CMAKE_SOURCE_DIR}/SDL2/")
+
+    set(SDL2_INCLUDE_DIRS "${SDL2_FOLDER}/include")
+    set(SDL2_LIBS "${SDL2_FOLDER}/lib/x64/SDL2.lib")
+    set(SDL2_DLLS "${SDL2_FOLDER}/lib/x64/SDL2.dll")
+    set(SDL2_DIR "${SDL2_FOLDER}/cmake/")
+    # On Linux, the library is found automatically if installed
+endif()
+
+
+# --- Locate SDL2 ---
+# Uses SDL2_DIR on Windows, on Linux it's found automatically
+find_package(SDL2 REQUIRED) 
+include_directories(${SDL2_INCLUDE_DIRS})
+
+
+#--- Include directories ---
+include_directories(${SDL2_INCLUDE_DIRS} ./)
+
+
+# --- Source files ---
+# Note: When new files are added, CMake has to be re-run
+# Alternatively, list files manually here
+file(GLOB SOURCES
+    "*.cpp"
+    "*.c"
+)
+add_executable(Snake main.cpp)
+target_link_libraries(Snake ${SDL2_LIBRARIES})
+
+
+# --- Copy SDL2 DLLs to the output folder on Windows ---
+if(WIN32)
+    foreach(DLL ${SDL2_DLLS})
+        add_custom_command(TARGET Snake POST_BUILD COMMAND
+            ${CMAKE_COMMAND} -E copy_if_different ${DLL} $<TARGET_FILE_DIR:Snake>)
+    endforeach()
+endif()