Bsckends: SDL2, GLFW: fixed ImGui_ImplXXXX_GetContentScaleXXX functions never using SDL 2.0.4 & GLFW 3.3 path in master.

Amend 9da3e6696a, 8269924c (was broken for master)

backends/imgui_impl_glfw.cpp

@@ -134,6 +134,7 @@
 
 // We gather version tests as define in order to easily see which features are version-dependent.
 #define GLFW_VERSION_COMBINED           (GLFW_VERSION_MAJOR * 1000 + GLFW_VERSION_MINOR * 100 + GLFW_VERSION_REVISION)
+#define GLFW_HAS_PER_MONITOR_DPI        (GLFW_VERSION_COMBINED >= 3300) // 3.3+ glfwGetMonitorContentScale
 #ifdef GLFW_RESIZE_NESW_CURSOR          // Let's be nice to people who pulled GLFW between 2019-04-16 (3.4 define) and 2019-11-29 (cursors defines) // FIXME: Remove when GLFW 3.4 is released?
 #define GLFW_HAS_NEW_CURSORS            (GLFW_VERSION_COMBINED >= 3400) // 3.4+ GLFW_RESIZE_ALL_CURSOR, GLFW_RESIZE_NESW_CURSOR, GLFW_RESIZE_NWSE_CURSOR, GLFW_NOT_ALLOWED_CURSOR
 #else

backends/imgui_impl_sdl2.cpp

@@ -123,6 +123,7 @@
 #else
 #define SDL_HAS_CAPTURE_AND_GLOBAL_MOUSE    0
 #endif
+#define SDL_HAS_PER_MONITOR_DPI             SDL_VERSION_ATLEAST(2,0,4)
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
 #define SDL_HAS_OPEN_URL                    SDL_VERSION_ATLEAST(2,0,14)
 #if SDL_HAS_VULKAN