Use os.fsencode() to support surrogates

Demo/zlib/minigzip.py

@@ -31,7 +31,7 @@ def compress(filename, input, output):
     write32(output, mtime)
     output.write(b'\002')                # ... slowest compression alg. ...
     output.write(b'\377')                # ... OS (=unknown) ...
-    bfilename = filename.encode(sys.getfilesystemencoding())
+    bfilename = os.fsencode(filename)
     output.write(bfilename + b'\000')    # ... original filename ...
 
     crcval = zlib.crc32(b'')

Lib/posixpath.py

@@ -262,7 +262,7 @@ def expanduser(path):
             return path
         userhome = pwent.pw_dir
     if isinstance(path, bytes):
-        userhome = userhome.encode(sys.getfilesystemencoding())
+        userhome = os.fsencode(userhome)
         root = b'/'
     else:
         root = '/'