add missing pkgconfig path.

component/gtk-2/buildout.cfg

@@ -36,7 +36,7 @@ configure-options =
 # XXX-Cedric : Why, god, why do I have to supply the -lXrender option to linker?
 environment = 
   PATH=${glib:location}/bin:${freetype:location}/bin:${pkgconfig:location}/bin:%(PATH)s
-  PKG_CONFIG_PATH=${glib:location}/lib/pkgconfig:${fontconfig:location}/lib/pkgconfig:${freetype:location}/lib/pkgconfig:${cairo:location}/lib/pkgconfig::${libXrender:location}/lib/pkgconfig
+  PKG_CONFIG_PATH=${glib:location}/lib/pkgconfig:${fontconfig:location}/lib/pkgconfig:${freetype:location}/lib/pkgconfig:${cairo:location}/lib/pkgconfig:${libXrender:location}/lib/pkgconfig:${pixman:location}/lib/pkgconfig:${libpng:location}/lib/pkgconfig
   CPPFLAGS=-I${cairo:location}/include/cairo -I${libX11:location}/include/X11 -I${libxcb:location}/include/xcb -I${libXau:location}/include/X11 -I${bzip2:location}/include -L${libXrender:location}/include -I${zlib:location}/include
   LDFLAGS=-L${cairo:location}/lib -Wl,-rpath=${cairo:location}/lib -L${libX11:location}/lib -Wl,-rpath=${libX11:location}/lib -L${libxcb:location}/lib -Wl,-rpath=${libxcb:location}/lib -L${libXau:location}/lib -Wl,-rpath=${libXau:location}/lib -L${bzip2:location}/lib -Wl,-rpath=${bzip2:location}/lib -L${libXrender:location}/lib -Wl,-rpath=${libXrender:location}/lib -lXrender -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib
   LD_LIBRARY_PATH=${render:location}/lib:${libX11:location}/lib:${libXrender:location}/lib