Thank you, Thien.
I know that much work and probably much knowledge too is involved in compiling an extension for Android and possibly for a proper version or processor (i've never compiled a PHP extension on my own for any OS). So there seems to be no out-of-box solution.
I know there is something like this https://www.phpforandroid.net
From your link Thien i see there is a linux installation, i don't know how it works, though. Modern distribution have phalcon onboard. I don't know whether this debian does.
I wouldn't like to root my phone for some time more.
And i did the most practical thing so far e-mailing Andro PHP developers.
If i know something interesting i'll write about it.
The topic should stay open.