[pp/XAttrMetadata] Only set "Where From" on macOS

Authored by: bashonly

yt_dlp/postprocessor/xattrpp.py

@@ -1,4 +1,5 @@
 import os
+import sys
 
 from .common import PostProcessor
 from ..utils import (
@@ -54,8 +55,8 @@ class XAttrMetadataPP(PostProcessor):
                     if infoname == 'upload_date':
                         value = hyphenate_date(value)
                     elif xattrname == 'com.apple.metadata:kMDItemWhereFroms':
-                        # NTFS ADS doesn't support colons in names
-                        if os.name == 'nt':
+                        # Colon in xattr name throws errors on Windows/NTFS and Linux
+                        if sys.platform != 'darwin':
                             continue
                         value = self.APPLE_PLIST_TEMPLATE % value
                     write_xattr(info['filepath'], xattrname, value.encode())