Allow Headers.add to get a list of parameters on *args

This ensures the order of parameters, which can be useful for issues
like supporting IE8 in flask's #2223

werkzeug/datastructures.py

@@ -1140,7 +1140,7 @@ def __iter__(self):
     def __len__(self):
         return len(self._list)
 
-    def add(self, _key, _value, **kw):
+    def add(self, _key, _value, *args, **kw):
         """Add a new header tuple to the list.
 
         Keyword arguments can specify additional parameters for the header
@@ -1153,9 +1153,15 @@ def add(self, _key, _value, **kw):
         The keyword argument dumping uses :func:`dump_options_header`
         behind the scenes.
 
+        In some cases, it would be needed to ensure the order of parameters.
+        For those cases, a list of ``(key, value)`` tuples can be passed in
+        *args.
+
         .. versionadded:: 0.4.1
             keyword arguments were added for :mod:`wsgiref` compatibility.
         """
+        if args:
+            _value = dump_options_header(_value, args)
         if kw:
             _value = _options_header_vkw(_value, kw)
         _value = _unicodify_header_value(_value)
@@ -2736,5 +2742,6 @@ def __repr__(self):
 # circular dependencies
 from werkzeug.http import dump_options_header, dump_header, generate_etag, \
     quote_header_value, parse_set_header, unquote_etag, quote_etag, \
-    parse_options_header, http_date, is_byte_range_valid
+    parse_options_header, http_date, is_byte_range_valid, \
+    dump_options_header_list
 from werkzeug import exceptions

werkzeug/http.py

@@ -212,7 +212,11 @@ def dump_options_header(header, options):
     segments = []
     if header is not None:
         segments.append(header)
-    for key, value in iteritems(options):
+    if isinstance(options, tuple):
+        iter_func = iter
+    else:
+        iter_func = iteritems
+    for key, value in iter_func(options):
         if value is None:
             segments.append(key)
         else: