Merge branch 'jk/quote-env-path-list-component'

A recent update to receive-pack to make it easier to drop garbage
objects made it clear that GIT_ALTERNATE_OBJECT_DIRECTORIES cannot
have a pathname with a colon in it (no surprise!), and this in turn
made it impossible to push into a repository at such a path.  This
has been fixed by introducing a quoting mechanism used when
appending such a path to the colon-separated list.

* jk/quote-env-path-list-component:
  t5615-alternate-env: double-quotes in file names do not work on Windows
  t5547-push-quarantine: run the path separator test on Windows, too
  tmp-objdir: quote paths we add to alternates
  alternates: accept double-quoted paths

Documentation/git.txt

@@ -871,6 +871,12 @@ Git so take care if using a foreign front-end.
 	specifies a ":" separated (on Windows ";" separated) list
 	of Git object directories which can be used to search for Git
 	objects. New objects will not be written to these directories.
++
+	Entries that begin with `"` (double-quote) will be interpreted
+	as C-style quoted paths, removing leading and trailing
+	double-quotes and respecting backslash escapes. E.g., the value
+	`"path-with-\"-and-:-in-it":vanilla-path` has two paths:
+	`path-with-"-and-:-in-it` and `vanilla-path`.
 
 `GIT_DIR`::
 	If the `GIT_DIR` environment variable is set then it