fixup! Add support for escaping $ with $$

src/zc/buildout/buildout.py

@@ -55,6 +55,7 @@ import tempfile
 import pprint
 import zc.buildout
 import zc.buildout.download
+from functools import partial
 
 PY3 = sys.version_info[0] == 3
 if PY3:
@@ -1732,7 +1733,7 @@ def _save_option(option, value, f):
 def _save_options(section, options, f):
     print_('[%s]' % section, file=f)
     try:
-        get_option = options._get
+        get_option = partial(options._get, last=False)
     except AttributeError:
         get_option = options.get
     for option in sorted(options):