libhybris support?
libhybris is a compatibility layer for loading Android libraries (compiled against Bionic) by glibc-based Linux applications. However, with some changes it can be compiled with musl as well. Caveats yet to be found, but I was able to utilize Android OpenGL libraries on at least two devices (Moto Droid 4 and Moto Z Play).
Does it make sense to package libhybris for postmarketOS, and if yes, what's the best way to do it? Building libhybris requires extracted Android headers, ideally from device's Android tree. SailfishOS compiles libhybris for each device, while UBPorts/Hallium tried to keep single libhybris build for multiple ones, but now provide at least two libhybris packages - normal version and libhybris-caf for Qualcomm devices due to changes in gralloc headers, making it binary incompatible.
Another problem than would be packaging device-specific Android bits. SFOS uses files from CyanogenMod/LineageOS install, but overrides init scripts and libs. Halium instead builds minimal Android rootfs and runs it inside LXC.