Portable: fix GIT_EDITOR call with spaces on Windows

editor.py

@@ -15,6 +15,7 @@
 
 from __future__ import print_function
 import os
+import portable
 import re
 import sys
 import subprocess
@@ -83,8 +84,9 @@ least one of these before using this command.""", file=sys.stderr)
       fd = None
 
       if re.compile("^.*[$ \t'].*$").match(editor):
-        args = [editor + ' "$@"', 'sh']
-        shell = True
+        # args = [editor + ' "$@"', 'sh']
+        # shell = True
+        (args, shell) = portable.prepare_editor_args(editor)
       else:
         args = [editor]
         shell = False

portable.py

@@ -274,3 +274,14 @@ def WaitForProcess():
     if child_process:
       child_process.stdin.close()
       child_process.wait()
+
+
+def prepare_editor_args(editor):
+  if isUnix():
+    args = [editor + ' "$@"', 'sh']
+    shell = True
+  else:
+    editor = re.sub('["\']', '', editor)
+    args = editor.rsplit()
+    shell = False
+  return (args, shell)