Problem building gd2 on Leopard

[David Garza]

I'd like to install gd2, so I can then install Maxima, but the gd2  
build is failing because it can't find xpm.h.  I have a copy of xpm.h  
in both /Developer/SDKs/MacOSX10.5.sdk/usr/X11/include/X11 and / 
Developer/SDKs/MacOSX10.4u.sdk/usr/X11/include/X11, but the complier  
can't seem to find them.  The command which fails is

if /bin/sh ./libtool --tag=CC --mode=compile /usr/bin/gcc-4.0 - 
DHAVE_CONFIG_H -I. -I. -I.   -I/opt/local/include/freetype2 -I/opt/ 
local/include -I/opt/local/include -I/usr/X11/include  -O2 -MT  
gdxpm.lo -MD -MP -MF ".deps/gdxpm.Tpo" -c -o gdxpm.lo gdxpm.c; \
	then mv -f ".deps/gdxpm.Tpo" ".deps/gdxpm.Plo"; else rm -f ".deps/ 
gdxpm.Tpo"; exit 1; fi
  /usr/bin/gcc-4.0 -DHAVE_CONFIG_H -I. -I. -I. -I/opt/local/include/ 
freetype2 -I/opt/local/include -I/opt/local/include -I/usr/X11/include  
-O2 -MT gdxpm.lo -MD -MP -MF .deps/gdxpm.Tpo -c gdxpm.c  -fno-common - 
DPIC -o .libs/gdxpm.o

Is there a problem with my X11 package?  Should I just modify the  
portfile to point it to the correct directories?

Thanks,
David