segfault in Xnest

I wanted to test the xcompmgr and so i compiled xserver with
--enable-composite, but it seems some structure initialization is
lacking. Here is the output of valgrind:
*********
==3187== Use of uninitialised value of size 4
==3187==    at 0x80AE662: compCheckWindow (compwindow.c:36)
==3187==    by 0x8074703: TraverseTree (window.c:223)
==3187==    by 0x80AE83F: compCheckTree (compwindow.c:64)
==3187==    by 0x80AEFB2: compCreateWindow (compwindow.c:299)
==3187==
==3187== Jump to the invalid address stated on the next line
==3187==    at 0x0: ???
==3187==    by 0x8074703: TraverseTree (window.c:223)
==3187==    by 0x80AE83F: compCheckTree (compwindow.c:64)
==3187==    by 0x80AEFB2: compCreateWindow (compwindow.c:299)
==3187==    Address 0x0 is not stack'd, malloc'd or free'd
Erreur de segmentation
*********
compwindow.c:36 is this line, it's GetWindowPixmap that is
uninitialized:
*********
PixmapPtr   pWinPixmap = (*pScreen->GetWindowPixmap) (pWin);
*********

I'm using CVS head with jhbuild.

I hope this will help.

@+