gtk fejl ved compile af mozilla

checking for gtk-config... no
checking for GTK - version >= 1.2.0... no
nogen der ved hvordan jeg kommer forbi denne fejl?

*** The gtk-config script installed by GTK could not be found.
*** If GTK was installed in PREFIX, make sure PREFIX/bin is in
*** your path, or set the GTK_CONFIG environment variable to the
*** full path to gtk-config.
*** GTK+ is available from ftp://ftp.gtk.org/pub/gtk
configure: error: Test for GTK failed.
*** Fix above errors and then restart with "make -f client.mk build"
make: *** [/cygdrive/c/mozilla/mozilla/Makefile] Error 1

C:\mozilla\mozilla>