Gtk + OSX

[electroteque <spam electroteque org>]

Hi, i finally manage to get pango going with that extra flag to CFLAGS. 
Now gtk broke,  with this

 gcc -DHAVE_CONFIG_H -I. -I. -I../.. -DG_LOG_DOMAIN=\"Gdk\" 
-DGDK_COMPILATION -I../.. -I../../gdk -I../../gdk 
-DGDK_PIXBUF_DISABLE_DEPRECATED -DGDK_DISABLE_DEPRECATED 
-DG_ENABLE_DEBUG -pthreads -I/usr/local/gtk/include/glib-2.0 
-I/usr/local/gtk/lib/glib-2.0/include 
-I/usr/local/gtk/include/pango-1.0 -I/usr/local/gtk/include/cairo 
-xobjective-c -I/usr/local/gtk/include -DG_DISABLE_DEPRECATED 
-I/usr/local/gtk/include -Wall -MT GdkQuartzView.lo -MD -MP -MF 
.deps/GdkQuartzView.Tpo -c GdkQuartzView.c  -fno-common -DPIC -o 
.libs/GdkQuartzView.o
gcc: unrecognized option `-pthreads'
In file included from GdkQuartzView.c:22:
GdkQuartzView.h:21:26: Quartz/Quartz.h: No such file or directory
In file included from GdkQuartzView.c:22:
GdkQuartzView.h:26: error: cannot find interface declaration for 
`NSView', superclass of `GdkQuartzView'
make[4]: *** [GdkQuartzView.lo] Error 1
make[3]: *** [all-recursive] Error 1
make[2]: *** [all] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

What is Quartz.h and where would it be ?  locate Quartz.h doesnt tell 
me anything.