Follow-up

[Sterling Smith <smithsp fusion gat com>]

I solved three problems, only to be stumped by a third:

1. I misspelled the environment variable - it has to be CFLAGS (not CC).  The value of CFLAGS which is working thus far is:
echo $CFLAGS
-I/usr/local/include/glib-2.0 -I/usr/local/include/cairo -I/usr/local/include/pango-1.0 -I/usr/local/include/atk-1.0

2. I had to move libconfig.h from the directory where I built glib to the directory 
/usr/local/include/glib-2.0
which is the default installation location.

3. I had to change the name of an include file to pango/pango-fontmap.h from pango/pangofc-fontmap.h.  (This was in gtk/gtksettings.c)

However, now I have the problem:

Making all in tests
/bin/sh ../../libtool  --tag=CC   --mode=link gcc  -DGDK_PIXBUF_DISABLE_DEPRECATED -I/usr/local/include/glib-2.0 -I/usr/local/include/cairo -I/usr/local/include/pango-1.0 -I/usr/local/include/atk-1.0 -Wall -export-dynamic  -o builder builder.o ../../gdk-pixbuf/libgdk_pixbuf-2.0.la ../../gdk/libgdk-x11-2.0.la ../../gtk/libgtk-x11-2.0.la -L/usr/X11/lib -R/usr/X11/lib -lXrender -lX11     -lm  
libtool: link: gcc -DGDK_PIXBUF_DISABLE_DEPRECATED -I/usr/local/include/glib-2.0 -I/usr/local/include/cairo -I/usr/local/include/pango-1.0 -I/usr/local/include/atk-1.0 -Wall -o .libs/builder builder.o  ../../gdk-pixbuf/.libs/libgdk_pixbuf-2.0.dylib -L/usr/local/lib ../../gdk/.libs/libgdk-x11-2.0.dylib -L/usr/X11/lib ../../gtk/.libs/libgtk-x11-2.0.dylib /Users/smithsp/Downloads/gtk+-2.18.9/gdk/.libs/libgdk-x11-2.0.dylib -lXinerama -lXext /usr/local/lib/libpangocairo-1.0.dylib /usr/local/lib/libpango-1.0.dylib /usr/local/lib/libcairo.dylib /usr/local/lib/libpixman-1.dylib /usr/local/lib/libfontconfig.dylib -lexpat /usr/local/lib/libpng14.dylib -lfreetype -lz -lSM -lICE /Users/smithsp/Downloads/gtk+-2.18.9/gdk-pixbuf/.libs/libgdk_pixbuf-2.0.dylib /usr/local/lib/libgio-2.0.dylib /usr/local/lib/libgobject-2.0.dylib /usr/local/lib/libgmodule-2.0.dylib /usr/local/lib/libglib-2.0.dylib /usr/local/lib/libintl.dylib /usr/local/lib/libiconv.dylib -lc -lXrender -lX11 -lm -pthread -framework Cocoa -framework CoreFoundation -framework Carbon
Undefined symbols:
  "_atk_relation_set_get_n_relations", referenced from:
      _test_widget in builder.o
  "_atk_object_ref_relation_set", referenced from:
      _test_widget in builder.o
  "_atk_relation_get_type", referenced from:
      _test_widget in builder.o
  "_atk_relation_set_get_relation", referenced from:
      _test_widget in builder.o
  "_atk_relation_get_relation_type", referenced from:
      _test_widget in builder.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

[etc.]

I really have no idea how to solve this issue.  Please let me know what I can do to build gtk+

Thanks,
Sterling