macros.cmake: PrintEnabledBackends should catch underscores.

Otherwise, "dos_soundblaster" doesn't show up in the list of backends for DOS.

cmake/macros.cmake

@@ -412,10 +412,10 @@ function(SDL_PrintSummary)
     PrintEnabledBackends("X11 libraries" "^SDL_VIDEO_DRIVER_X11_([A-Z0-9]*)$")
   endif()
   PrintEnabledBackends("Render drivers" "^SDL_VIDEO_RENDER_([A-Z0-9_]*)$")
-  PrintEnabledBackends("GPU drivers" "^SDL_GPU_([A-Z0-9]*)$")
-  PrintEnabledBackends("Audio drivers" "^SDL_AUDIO_DRIVER_([A-Z0-9]*)$")
-  PrintEnabledBackends("Joystick drivers" "^SDL_JOYSTICK_([A-Z0-9]*)$")
-  PrintEnabledBackends("Camera drivers" "^SDL_CAMERA_DRIVER_([A-Z0-9]*)$")
+  PrintEnabledBackends("GPU drivers" "^SDL_GPU_([A-Z0-9_]*)$")
+  PrintEnabledBackends("Audio drivers" "^SDL_AUDIO_DRIVER_([A-Z0-9_]*)$")
+  PrintEnabledBackends("Joystick drivers" "^SDL_JOYSTICK_([A-Z0-9_]*)$")
+  PrintEnabledBackends("Camera drivers" "^SDL_CAMERA_DRIVER_([A-Z0-9_]*)$")
   message(STATUS "")
 
   if(UNIX)