Footnotes profileration with null header/footer

[Nicolas Sceaux]

Hi,

Using today's git LilyPond, the following snippet gives weird results:
the footnote is printed several times in header and footer, and on
several pages.

\version "2.15.32"

\paper {
 oddHeaderMarkup = \markup\null
 evenHeaderMarkup = \markup\null
 oddFooterMarkup = \markup\null
 evenFooterMarkup = \markup\null
}

{
 \footnote #'(0 . -1) #'NoteHead "a footnote"
 c'1 \pageBreak
 c'1
}

When using e.g. "" instead of \markup\null then everthing seems fine.

Nicolas