(svn r22003) -Document [FS#3447]: that SDL for Mac OS X might very well be unusable

config.lib

@@ -2265,6 +2265,12 @@ detect_sdl() {
 		return 0
 	fi
 
+	if [ "$os" = "OSX" ]; then
+		log 1 "WARNING: sdl is known to fail on some versions of Mac OS X"
+		log 1 "WARNING: with some hardware configurations. Use at own risk!"
+		sleep 5
+	fi
+
 	if [ "$with_sdl" = "1" ] || [ "$with_sdl" = "" ] || [ "$with_sdl" = "2" ]; then
 		sdl_config="sdl-config"
 	else

known-bugs.txt

@@ -39,7 +39,6 @@ officially supporting Mac OS X again. For now it remains unsupported and
 we only apply bug fixes provided by the community but we are unable to fix
 these bugs ourselves.
 
-- 3447	[OSX] SDL port is unuseable
 - 2484	[OSX] Cannot enter CJK characters
 
 2.1) Known bugs that will not be solved
@@ -212,6 +211,15 @@ OpenTTD not properly resizing with SDL on X [FS#3305]
 	and GNOME's. With the XFCE's and LXDE's window managers the resize
 	event is sent when the user releases the mouse.
 
+Incorrect colours, crashes upon exit, debug warnings and smears upon
+window resizing with SDL on Mac OS X [FS#3447]
+	Video handling with (lib)SDL under Mac OS X is known to fail on some
+	versions of Mac OS X with some hardware configurations. Some of the
+	problems happen only under some circumstances whereas others are
+	always present.
+	We suggest that the SDL video/sound backend is not used for OpenTTD
+	in combinations with Mac OS X.
+
 Train crashes entering same junction from block and path signals [FS#3928]
 	When a train has reserved a path from a path signal to a two way
 	block signal and the reservation passes a path signal through the