Build the offscreen video driver by default.

CMakeLists.txt

@@ -497,7 +497,7 @@ dep_option(SDL_VULKAN              "Enable Vulkan support" ON "ANDROID OR APPLE
 set_option(SDL_METAL               "Enable Metal support" ${APPLE})
 set_option(SDL_KMSDRM              "Use KMS DRM video driver" ${UNIX_SYS})
 dep_option(SDL_KMSDRM_SHARED       "Dynamically load KMS DRM support" ON "SDL_KMSDRM" OFF)
-set_option(SDL_OFFSCREEN           "Use offscreen video driver" OFF)
+set_option(SDL_OFFSCREEN           "Use offscreen video driver" ON)
 option_string(SDL_BACKGROUNDING_SIGNAL "number to use for magic backgrounding signal or 'OFF'" OFF)
 option_string(SDL_FOREGROUNDING_SIGNAL "number to use for magic foregrounding signal or 'OFF'" OFF)
 set_option(SDL_HIDAPI              "Enable the HIDAPI subsystem" ON)

configure.ac

@@ -2398,8 +2398,8 @@ CheckDummyVideo()
 CheckOffscreenVideo()
 {
     AC_ARG_ENABLE(video-offscreen,
-[AS_HELP_STRING([--enable-video-offscreen], [use offscreen video driver [default=no]])],
-                  , enable_video_offscreen=no)
+[AS_HELP_STRING([--enable-video-offscreen], [use offscreen video driver [default=yes]])],
+                  , enable_video_offscreen=yes)
     if test x$enable_video_offscreen = xyes; then
         AC_DEFINE(SDL_VIDEO_DRIVER_OFFSCREEN, 1, [ ])
         SOURCES="$SOURCES $srcdir/src/video/offscreen/*.c"