bug#45847: 27.1; Shouldn't gnus go along with leading space in mime word, like mutt

[積丹尼 Dan Jacobson]

mutt can deal fine with these:
Subject: =?UTF-8?B? 4pyoIEN1cnJpY3VsdW0gY29tIEZvdG8=?=
                   ^
From: =?UTF-8?B? U2ltb25lIEzDqm1lcw=?= <simone74@example.net>
                ^
(note odd space at start of strings)

I thought gnus was all about smoothing over others mistakes (with no way
to switch on warnings...) But in this case it (rightly) says "enough is
enough" and refuses to cooperate with the rule breaker. (Wonder what
gmail does here.)