[Minor] Lua_mime: Quote charser

diff --git a/lualib/lua_mime.lua b/lualib/lua_mime.lua
index e116f897b3f5475a15df86204a0e8237b0fe26b9..f01f4003a0f5fc5a71b47215ece380c8d980a6f4 100644 (file)
--- a/lualib/lua_mime.lua
+++ b/lualib/lua_mime.lua
@@ -298,7 +298,7 @@ local function do_replacement (task, part, mp, replacements,
     end
 
     if is_multipart then
-      out[#out + 1] = {string.format('Content-Type: %s; charset=utf-8%s'..
+      out[#out + 1] = {string.format('Content-Type: %s; charset="utf-8"%s'..
           'Content-Transfer-Encoding: %s',
           ct, newline_s, cte), true}
       out[#out + 1] = {'', true}