libxft-dev problem

[quirin <linqs@gmx.de>]

during apt-get upgrade i encountered the following problem with libxft2-dev. 
(i use sid)

bigfatmama:/home/quirin/tmp# apt-get upgrade
Reading Package Lists... Done
Building Dependency Tree... Done
You might want to run `apt-get -f install' to correct these.
The following packages have unmet dependencies:
  libxft-dev: Depends: libxft2 (= 2.1.2-5) but 2.1.2-6 is installed
E: Unmet dependencies. Try using -f

using the -f option show the following unsatisfying output

bigfatmama:/home/quirin/tmp# apt-get -f install
Reading Package Lists... Done
Building Dependency Tree... Done
Correcting dependencies... Done
The following extra packages will be installed:
  libxft-dev
The following packages will be upgraded:
  libxft-dev
1 upgraded, 0 newly installed, 0 to remove and 6 not upgraded.
35 not fully installed or removed.
Need to get 0B/60.2kB of archives.
After unpacking 4096B disk space will be freed.
Do you want to continue? [Y/n] Y
(Reading database ... 191853 files and directories currently installed.)
Preparing to replace libxft-dev 2.1.2-5 
(using .../libxft-dev_2.1.2-6_i386.deb) ...
diversion of /usr/X11R6/include/X11/Xft/Xft.h 
to /usr/X11R6/include/X11/Xft/Xft1.h by libxft-dev
Removing `diversion of /usr/X11R6/include/X11/Xft/Xft.h 
to /usr/X11R6/include/X11/Xft/Xft1.h by libxft-dev'
dpkg-divert: rename involves overwriting `/usr/X11R6/include/X11/Xft/Xft.h' 
with
  different file `/usr/X11R6/include/X11/Xft/Xft1.h', not allowed
dpkg: error processing /var/cache/apt/archives/libxft-dev_2.1.2-6_i386.deb 
(--unpack):
 subprocess pre-installation script returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/libxft-dev_2.1.2-6_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

so far i wasn't able to fix this problem on my computer. does anyone have an 
idea how to deal with that?