wayland: Prefer to use CSS names for cursors, falling back to X11

SDL3's Wayland code already uses the CSS names exclusively with no
fallback, but since SDL2 has historically used the older names, keeping
them as a fallback makes sense if the CSS names don't work out.

[smcv: Added commit message]
Tested-by: Simon McVittie <smcv@collabora.com>

src/video/wayland/SDL_waylandmouse.c

@@ -160,6 +160,8 @@ static SDL_bool wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorDa
 {
     struct wl_cursor_theme *theme = NULL;
     struct wl_cursor *cursor;
+    const char *cssname = NULL;
+    const char *legacyname = NULL;
 
     char *xcursor_size;
     int size = 0;
@@ -233,46 +235,65 @@ static SDL_bool wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorDa
     /* Next, find the cursor from the theme... */
     switch (cdata->system_cursor) {
     case SDL_SYSTEM_CURSOR_ARROW:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "left_ptr");
+        cssname = "default";
+        legacyname = "left_ptr";
         break;
     case SDL_SYSTEM_CURSOR_IBEAM:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "xterm");
+        cssname = "text";
+        legacyname = "xterm";
         break;
     case SDL_SYSTEM_CURSOR_WAIT:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "watch");
+        cssname = "wait";
+        legacyname = "watch";
         break;
     case SDL_SYSTEM_CURSOR_CROSSHAIR:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "tcross");
+        cssname = "crosshair";
+        legacyname = "tcross";
         break;
     case SDL_SYSTEM_CURSOR_WAITARROW:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "watch");
+        cssname = "progress";
+        legacyname = "watch";
         break;
     case SDL_SYSTEM_CURSOR_SIZENWSE:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "top_left_corner");
+        cssname = "nwse-resize";
+        legacyname = "top_left_corner";
         break;
     case SDL_SYSTEM_CURSOR_SIZENESW:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "top_right_corner");
+        cssname = "nesw-resize";
+        legacyname = "top_right_corner";
         break;
     case SDL_SYSTEM_CURSOR_SIZEWE:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "sb_h_double_arrow");
+        cssname = "ew-resize";
+        legacyname = "sb_h_double_arrow";
         break;
     case SDL_SYSTEM_CURSOR_SIZENS:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "sb_v_double_arrow");
+        cssname = "ns-resize";
+        legacyname = "sb_v_double_arrow";
         break;
     case SDL_SYSTEM_CURSOR_SIZEALL:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "fleur");
+        cssname = "move";
+        legacyname = "fleur";
         break;
     case SDL_SYSTEM_CURSOR_NO:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "pirate");
+        cssname = "not-allowed";
+        legacyname = "pirate";
         break;
     case SDL_SYSTEM_CURSOR_HAND:
-        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "hand2");
+        cssname = "pointer";
+        legacyname = "hand2";
         break;
     default:
         SDL_assert(0);
         return SDL_FALSE;
     }
 
+    cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, cssname);
+
+    /* try the legacy name if the fancy new CSS name doesn't work... */
+    if (!cursor) {
+        cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, legacyname);
+    }
+
     /* Fallback to the default cursor if the chosen one wasn't found */
     if (!cursor) {
         cursor = WAYLAND_wl_cursor_theme_get_cursor(theme, "default");