Comment 2 for bug 266166

I can reproduce this bug also.

Here's a diff what happened to me:
diff -u mail.valid mail.invalid

 Content-Disposition: attachment;
filename=configure.in.pre-pkgconfig.patch
-Content-Type: text/x-patch;
name=configure.in.pre-pkgconfig.patch; charset=UTF-8
+Content-Type: text/x-patch;
name=configure.in.pre-pkgconfig.patch;
+ charset=UTF-8
 Content-Transfer-Encoding: base64

And this was _inside_ gpg-signed block.
Mailman should not alter that section at all, right?
X-Mailman-Version: 2.1.4

Yours,
 Toni Willberg <email address hidden>