There is no libpng, libfreetype, libfontconfig, libexpat.. on android native system.
So I think we need to register these to servo's submodule (mozilla-servo) for android.
Those submodules are on our github.
https://github.com/webconvforge/libfreetype2
https://github.com/webconvforge/libexpat
https://github.com/webconvforge/fontconfig
https://github.com/webconvforge/libpng

As our plan, these libraries can be located on <servo root>/src/platform/android.

After all of modified submodules are merged, we can do pull request servo. 
you can see the candidate of servo'PR, take a look https://github.com/webconv/servo/tree/PRcand3

By the way,

This convention already used in Makefile.in of rust-css like below.
RUSTFLAGS += -L . -L ../../netsurfcss/libcss -L ../../libparserutils/libparserutils -L ../../wapcaplet/libwapcaplet
and rust-netsurfcss, rust-wapcaplet is same because libcss and libwapcalet are not existed on system.
So I thought this would be fine..
Plz can you suggest another way, If you have.