GNU Radio on Android

Since I have little else to do at the moment than playing with my phone,
I debugged the USB OTG port of my Sony Z5, which led me to install the
rtl-sdr driver, which led me to install some non-GNU Radio application
to test the SDR capability of the phone, and it works. I haven't learnt
anything in the process.

I do have Tom's detailed description on compiling GNU Radio but I am afraid
the 2017 flowchart for 3.7 is no longer valid, and I have Bastian's video
showing off GNU Radio 3.8 on android which also does not teach me much other
than making me envious.

Is there some documentation on getting started, considering I have absolutely
no clue on how to cross compile to Android ?

Thanks, JM

--
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
25000 Besancon, France