Disk (Windows): make / an alias of C:\ for --disk-folders

src/data/help.json

@@ -947,7 +947,8 @@
         },
         {
             "long": "disk-folders",
-            "desc": "A colon (semicolon on Windows) separated list of folder paths for the disk output",
+            "desc": "A colon (semicolon on Windows) separated list of folder paths to be detected",
+            "remark": "On Windows, a drive latter must be upper cased and end with \"\\\". \"/\" is used as an alias of the system drive. eg. \"/\" is the alias of \"C:\\\".",
             "arg": {
                 "type": "path",
                 "default": "Auto detection using mount-points"

src/detection/disk/disk_windows.c

@@ -15,6 +15,13 @@ const char* ffDetectDisksImpl(FFDiskOptions* options, FFlist* disks)
 
     FF_STRBUF_AUTO_DESTROY buffer = ffStrbufCreate();
 
+    // For cross-platform portability; used by `presets/examples/13.jsonc`
+    if (__builtin_expect(options->folders.length == 1 && options->folders.chars[0] == '/', 0))
+    {
+        ffStrbufSetS(&options->folders, getenv("SystemDrive"));
+        ffStrbufEnsureEndsWithC(&options->folders, '\\');
+    }
+
     for(uint32_t i = 0; i < length; i++)
     {
         wchar_t* mountpoint = buf + i;