Problem building libsepol on some systems

[Rafał Miłecki]

Getting straight to the topic I get this error with my custom GitLab
builder (based on Ubuntu 20.04):

make[3]: Entering directory '/builds/openwrt/openwrt-21.02/package/libs/libsepol'
mkdir -p /builds/openwrt/openwrt-21.02/dl
SHELL= flock /builds/openwrt/openwrt-21.02/tmp/.libsepol-3.2.tar.gz.flock -c '  	/builds/openwrt/openwrt-21.02/scripts/download.pl "/builds/openwrt/openwrt-21.02/dl" "libsepol-3.2.tar.gz" "dfc7f662af8000116e56a01de6a0394ed79be1b34b999e551346233c5dd19508" "" "https://github.com/SELinuxProject/selinux/releases/download/3.2"    '
rm -rf /builds/openwrt/openwrt-21.02/tmp/stage-libsepol
mkdir -p /builds/openwrt/openwrt-21.02/tmp/stage-libsepol/host /builds/openwrt/openwrt-21.02/staging_dir/target-mipsel_24kc_musl/packages
install -d -m0755 /builds/openwrt/openwrt-21.02/tmp/stage-libsepol/usr/include
cp -fpR /builds/openwrt/openwrt-21.02/build_dir/target-mipsel_24kc_musl/libsepol-3.2/ipkg-install/usr/include/* /builds/openwrt/openwrt-21.02/tmp/stage-libsepol/usr/include/
cp: cannot stat '/builds/openwrt/openwrt-21.02/build_dir/target-mipsel_24kc_musl/libsepol-3.2/ipkg-install/usr/include/*': No such file or directory
make[3]: *** [Makefile:98: /builds/openwrt/openwrt-21.02/staging_dir/target-mipsel_24kc_musl/stamp/.libsepol_installed] Error 1
make[3]: Leaving directory '/builds/openwrt/openwrt-21.02/package/libs/libsepol'
time: package/libs/libsepol/compile#0.32#0.27#0.51
     ERROR: package/libs/libsepol failed to build.


I did some debugging and I can share some hints but I'm clueless about
the solution though.

1. Other targets
Above error comes from building ramips/mt7621. I can't reproduce it
building bcm53xx or bcm4908.

2. Local builds
On my local system directory
build_dir/target-mipsel_24kc_musl/libsepol-3.2/ipkg-install/usr/include/
is populated with headers. It seems to be done by
make package/libsepol/compile V=s
during its "make -C include install" step

3. # CONFIG_PACKAGE_libsepol is not set
On both systems I have PACKAGE_libsepol actually disabled. I don't even
know why my local builds compile that package.

4. Setting PACKAGE_libsepol=y
I made my GitLab / Ubuntu 20.04 build actually set PACKAGE_libsepol=y
but it results in exactly the same error. It seems that package just
doesn't get properly build on that system.

5. Broken package?
I suspect this package / its dependencies may be just broken. There was
some problem with buildbot and 3.2 → 3.3 bump too, see commit
ae4069c577fc ("Revert "libsepol: update to version 3.3"").
Is that maybe host packge that depends on target package that doesn't
always get build?