`kmod-video-v4l2loopback`: Build fails: Wants to build against buildhost's kernel, not target's kernel.

[dreirund]

Ahoj,

when I try to build kmod-video-v4l2loopback from the handsomefeed feed, it fails because it wants to build the module for the buildhosts's kernel and not for the target kernel.

The target kernel would be version 5.10.33,
where the buildhosts kernel is 5.19.0-pf5-longcmdline-custom (uname -r).

After a failing make -j6, here the terminal output of
make -j1 V=sc package/feeds/handsomefeed/kmod-video-v4l2loopback/compile:

[...]
make -C "/[...]/build_dir/target-aarch64_cortex-a53+neon_musl/linux-msm89xx_msm8916/video-v4l2loopback-baf9de27" ARCH="arm64" CROSS_COMPILE="aarch64-openwrt-linux-musl-" SUBDIRS="/[...]/build_dir/target-aarch64_cortex-a53+neon_musl/linux-msm89xx_msm8916/linux-5.10.33" v4l2loopback
make[3]: Entering directory '/[...]/build_dir/target-aarch64_cortex-a53+neon_musl/linux-msm89xx_msm8916/video-v4l2loopback-baf9de27'
Building v4l2-loopback driver...
make -C /lib/modules/`uname -r`/build M=/[...]/build_dir/target-aarch64_cortex-a53+neon_musl/linux-msm89xx_msm8916/video-v4l2loopback-baf9de27 modules
make[4]: Entering directory '/usr/lib/modules/5.19.0-pf5-longcmdline-custom/build'
Makefile:701: arch/arm64/Makefile: No such file or directory
make[4]: *** No rule to make target 'arch/arm64/Makefile'.  Stop.
[...]

Note that it enters the directory /usr/lib/modules/5.19.0-pf5-longcmdline-custom/build, which belongs to the buildhost's kernel and should not be dealt with at all here.

→ Full package build terminal output.

• grep -i v4l2loopback .config:
  CONFIG_PACKAGE_kmod-video-v4l2loopback=m
• → Full .config.