installing gtk+-2.4.13

[Reik H. Börger <reikhboerger gmx de>]

Hi,

I try to install gtk+-2.4.13 on Mac OSX. I always get the following 
output,when I type
./configure

...
...
checking for TIFFReadScanline in -ltiff... no
checking for TIFFWriteScanline in -ltiff... no
checking for TIFFFlushData in -ltiff34... no
configure: WARNING: *** TIFF plug-in will not be built (TIFF library 
not found) ***
configure: error:
*** Checks for TIFF loader failed. You can build without it by passing
*** --without-libtiff to configure but some programs using GTK+ may
*** not work properly

What's wrong here? I reinstalled the tiff-library and I do not know, 
why it can't be found...
Can anyone help me?
Thanks
Reik