Examples: Comments about GLFW/SDL versions

examples/imgui_impl_glfw.cpp

@@ -1,6 +1,7 @@
 // dear imgui: Platform Binding for GLFW
 // This needs to be used along with a Renderer (e.g. OpenGL3, Vulkan..)
 // (Info: GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.)
+// (Requires: GLFW 3.1+)
 
 // Implemented features:
 //  [X] Platform: Clipboard support.

examples/imgui_impl_sdl.cpp

@@ -1,6 +1,7 @@
 // dear imgui: Platform Binding for SDL2
 // This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
 // (Info: SDL2 is a cross-platform general purpose library for handling windows, inputs, graphics context creation, etc.)
+// (Requires: SDL 2.0. Prefer SDL 2.0.4+ for full feature support.)
 
 // Implemented features:
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
@@ -49,7 +50,6 @@
 
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    SDL_VERSION_ATLEAST(2,0,4)
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
-#define SDL_HAS_MOUSE_FOCUS_CLICKTHROUGH    SDL_VERSION_ATLEAST(2,0,5)
 #if !SDL_HAS_VULKAN
 static const Uint32 SDL_WINDOW_VULKAN = 0x10000000;
 #endif