external_files: allow specifying --cover-art-whitelist filenames

Fixes https://github.com/mpv-player/mpv/discussions/14520.

player/external_files.c

@@ -30,20 +30,6 @@
 #include "options/path.h"
 #include "external_files.h"
 
-// Stolen from: vlc/-/blob/master/modules/meta_engine/folder.c#L40
-// sorted by priority (descending)
-static const char *const cover_files[] = {
-    "AlbumArt",
-    "Album",
-    "cover",
-    "front",
-    "AlbumArtSmall",
-    "Folder",
-    ".folder",
-    "thumb",
-    NULL
-};
-
 // Needed for mp_might_be_subtitle_file
 char **sub_exts;
 
@@ -70,11 +56,13 @@ static int test_ext(MPOpts *opts, bstr ext)
     return -1;
 }
 
-static int test_cover_filename(bstr fname)
+static int test_cover_filename(bstr fname, char **cover_files)
 {
     for (int n = 0; cover_files[n]; n++) {
         if (bstrcasecmp(bstr0(cover_files[n]), fname) == 0) {
-            return MP_ARRAY_SIZE(cover_files) - n;
+            size_t size = n;
+            while (cover_files[++size]);
+            return size - n;
         }
     }
     return 0;
@@ -198,8 +186,8 @@ static void append_dir_subtitles(struct mpv_global *global, struct MPOpts *opts,
         if (bstr_find(tmp_fname_trim, f_fname_trim) >= 0 && fuzz >= 1)
             prio |= 2; // contains the movie name
 
-        if (type == STREAM_VIDEO && opts->coverart_whitelist && prio == 0)
-            prio = test_cover_filename(tmp_fname_trim);
+        if (type == STREAM_VIDEO && prio == 0)
+            prio = test_cover_filename(tmp_fname_trim, opts->coverart_whitelist);
 
         // doesn't contain the movie name
         // don't try in the mplayer subtitle directory