Compile libiconv with glib

Some platforms doesn't have iconv_open().

component/glib/buildout.cfg

 [buildout]
 extends =
   ../gettext/buildout.cfg
+  ../libiconv/buildout.cfg
   ../zlib/buildout.cfg
 
 [glib]
@@ -15,6 +16,6 @@ configure-options =
   --with-libiconv=gnu
 
 environment =
-  CPPFLAGS=-I${zlib:location}/include -I${gettext:location}/include
-  LDFLAGS=-L${zlib:location}/lib -Wl,-rpath,${zlib:location}/lib -L${gettext:location}/lib -Wl,-rpath,${gettext:location}/lib
+  CPPFLAGS=-I${zlib:location}/include -I${gettext:location}/include -I${libiconv:location}/include
+  LDFLAGS=-L${zlib:location}/lib -Wl,-rpath,${zlib:location}/lib -L${gettext:location}/lib -Wl,-rpath,${gettext:location}/lib -L${libiconv:location}/lib -Wl,-rpath,${libiconv:location}/lib
   PATH=${gettext:location}/bin:%(PATH)s