It was not copying the include dir files nor generating the pkgconfig files. Make install have the caveat of also installing docs, which we don't need for the build, but did not find a way to disable them.
Currently is needed to use rust nightly to cross-build the latest sequoia version for Android.
Before building again is needed to run, on the build machine:
rustup default nightly
rustup update nightly
rustup component add rust-src
rustup target add aarch64-linux-android armv7-linux-androideabi i686-linux-android x86_64-linux-android