how to config garnome build to use libpng in /usr/local?

[cc <nyvsld gmail com>]

hi,
im building garnome 2.10.2 on a Debian 3.1 testing system, using gcc-4.0.1,

'make paranoid-install' failed with these text:

 failed to load "./stock_about_16.png": Couldn't recognize the image  
file format for file './stock_about_16.png'

i found its a gtk+ error, so i go to 'gtk+-2.6.8/gdk-pixbuf' and type

  make gdk-pixbuf.loaders

then it says:

g_module_open() failed for
/home/me/src/garnome-2.10.2/platform/gtk+/work/main.d/gtk+-2.6.8/gdk-pixbuf/libpixbufloader-png.la:
/usr/local/lib/libpng12.so.0: undefined symbol: deflate

both zlib and libpng installed in /usr/local

so , how can i configure the garnome build system to make it use libs
in /usr/local ?