[bug#51771] Binder kernel module missing

[phodina]

Unfortunately, as stated above the binder interface is missing. I looked for 
the kernel module but couldn't find it. As the /proc/config.gz is not present I 
can't verify it's enabled.

$ find /run/booted-system/kernel/lib/modules/5.14.17-gnu/kernel/ -iname 
"*binder*"
$ cat /proc/cmdline
BOOT_IMAGE=/gnu/store/fr1cwmbn19hyrs3wxr5sqr7iy4cj674y-linux-libre-waydroid-5.14.17/bzImage
 --root=/dev/mapper/cryptsystem 
--system=/gnu/store/8g26gi6v9dni0cagc3l1ny8shyz8r38h-system 
--load=/gnu/store/8g26gi6v9dni0cagc3l1ny8shyz8r38h-system/boot 
modprobe.blacklist=usbmouse,usbkbd quiet

Therefore the waydroid userspace manager also doesn't work:

# waydroid.py init
[19:40:05] Failed to load binder driver
[19:40:06] modprobe: FATAL: Module binder_linux not found in directory 
/run/booted-system/kernel/lib/modules/5.14.17-gnu
[19:40:06] ERROR: Binder node "binder" for waydroid not found
[19:40:06] See also: <https://github.com/waydroid>
Run 'waydroid log' for details.

$ waydroid.py log
(006323) [19:40:05] % modprobe binder_linux 
devices="anbox-binder,anbox-vndbinder,anbox-hwbinder"
modprobe: FATAL: Module binder_linux not found in directory 
/run/booted-system/kernel/lib/modules/5.14.17-gnu
(006323) [19:40:05] Failed to load binder driver
(006323) [19:40:06] modprobe: FATAL: Module binder_linux not found in directory 
/run/booted-system/kernel/lib/modules/5.14.17-gnu
(006323) [19:40:06] ERROR: Binder node "binder" for waydroid not found
(006323) [19:40:06] See also: <https://github.com/waydroid>
(006323) [19:40:06] Traceback (most recent call last):
  File 
"/gnu/store/iprc2yqsx5zi8nc2g3nqvlmlqzbw7nrf-waydroid-1.2.0/lib/waydroid/tools/__init__.py",
 line 54, in main

My conclusion is the module is not enabled and built. It could be do the the 
extended match-lambda expression as I'm not Guile guru.

The patch related to waydroid can be find here [1].

[1] https://issues.guix.gnu.org/51737