emscripten, wayland, x11: Map SIZEALL to "all-scroll" instead of "move"

These previously mapped SIZEALL to "move", but "move" is not guaranteed
to be a four-pointed arrow: according to the CSS spec, it's actually
intended to be a drag-and-drop cursor, analogous to "alias" and "copy".
Map it to "all-scroll" instead, as in Wayland: while this is *also* not
semantically guaranteed to be a four-pointed arrow, it is at least
*suggested* to make it a four-pointed arrow.

Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit aa6c390bbd)

src/video/emscripten/SDL_emscriptenmouse.c

@@ -172,7 +172,7 @@ static SDL_Cursor *Emscripten_CreateSystemCursor(SDL_SystemCursor id)
         cursor_name = "ns-resize";
         break;
     case SDL_SYSTEM_CURSOR_SIZEALL:
-        cursor_name = "move";
+        cursor_name = "all-scroll";
         break;
     case SDL_SYSTEM_CURSOR_NO:
         cursor_name = "not-allowed";

src/video/wayland/SDL_waylandmouse.c

@@ -271,7 +271,7 @@ static SDL_bool wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorDa
         legacyname = "sb_v_double_arrow";
         break;
     case SDL_SYSTEM_CURSOR_SIZEALL:
-        cssname = "move";
+        cssname = "all-scroll";
         legacyname = "fleur";
         break;
     case SDL_SYSTEM_CURSOR_NO:

src/video/x11/SDL_x11mouse.c

@@ -270,7 +270,7 @@ static SDL_Cursor *X11_CreateSystemCursor(SDL_SystemCursor id)
         break;
     case SDL_SYSTEM_CURSOR_SIZEALL:
         shape = XC_fleur;
-        xcursorname = "move";
+        xcursorname = "all-scroll";
         break;
     case SDL_SYSTEM_CURSOR_NO:
         shape = XC_pirate;