T23362 docker: add kselftest build dependencies to gcc-8 and clang-10

[gctucker]

Add build dependencies for x86, arm and arm64 to the gcc-8 and
clang-10 Docker images. This causes some duplication, but there is no
easy way around it at the moment.

[gctucker]

Diff of tests being built without and with this PR, with gcc-8 on arm64 defconfig+kselftest:

@@ -13496,71 +12583,71 @@
 	echo "cd \$ROOT" >> /root/build/_kselftest_/run_kselftest.sh; \
 done;
 Emit Tests for android
-Skipping non-existent dir: arm64
+Emit Tests for arm64
 Skipping non-existent dir: bpf
-Skipping non-existent dir: breakpoints
-Skipping non-existent dir: capabilities
-Skipping non-existent dir: cgroup
-Skipping non-existent dir: clone3
-Skipping non-existent dir: core
+Emit Tests for breakpoints
+Emit Tests for capabilities
+Emit Tests for cgroup
+Emit Tests for clone3
+Emit Tests for core
 Emit Tests for cpufreq
 Emit Tests for cpu-hotplug
-Skipping non-existent dir: drivers/dma-buf
-Skipping non-existent dir: efivarfs
+Emit Tests for drivers/dma-buf
+Emit Tests for efivarfs
 Skipping non-existent dir: exec
-Skipping non-existent dir: filesystems
+Emit Tests for filesystems
 Skipping non-existent dir: filesystems/binderfs
-Skipping non-existent dir: filesystems/epoll
-Skipping non-existent dir: firmware
-Skipping non-existent dir: fpu
+Emit Tests for filesystems/epoll
+Emit Tests for firmware
+Emit Tests for fpu
 Emit Tests for ftrace
 Emit Tests for futex
 Emit Tests for intel_pstate
-Skipping non-existent dir: ipc
-Skipping non-existent dir: ir
-Skipping non-existent dir: kcmp
+Emit Tests for ipc
+Emit Tests for ir
+Emit Tests for kcmp
 Skipping non-existent dir: kexec
 Skipping non-existent dir: kvm
 Emit Tests for lib
 Emit Tests for livepatch
 Emit Tests for lkdtm
-Skipping non-existent dir: membarrier
-Skipping non-existent dir: memfd
+Emit Tests for membarrier
+Emit Tests for memfd
 Emit Tests for memory-hotplug
-Skipping non-existent dir: mincore
-Skipping non-existent dir: mount
-Skipping non-existent dir: mqueue
+Emit Tests for mincore
+Emit Tests for mount
+Emit Tests for mqueue
 Emit Tests for net
 Emit Tests for net/forwarding
-Skipping non-existent dir: net/mptcp
-Skipping non-existent dir: netfilter
-Skipping non-existent dir: nsfs
+Emit Tests for net/mptcp
+Emit Tests for netfilter
+Emit Tests for nsfs
 Skipping non-existent dir: pidfd
-Skipping non-existent dir: pid_namespace
+Emit Tests for pid_namespace
 Skipping non-existent dir: powerpc
-Skipping non-existent dir: proc
+Emit Tests for proc
 Emit Tests for pstore
-Skipping non-existent dir: ptrace
-Skipping non-existent dir: openat2
-Skipping non-existent dir: rseq
-Skipping non-existent dir: rtc
-Skipping non-existent dir: seccomp
-Skipping non-existent dir: sigaltstack
-Skipping non-existent dir: size
+Emit Tests for ptrace
+Emit Tests for openat2
+Emit Tests for rseq
+Emit Tests for rtc
+Emit Tests for seccomp
+Emit Tests for sigaltstack
+Emit Tests for size
 Skipping non-existent dir: sparc64
-Skipping non-existent dir: splice
+Emit Tests for splice
 Emit Tests for static_keys
-Skipping non-existent dir: sync
+Emit Tests for sync
 Emit Tests for sysctl
 Skipping non-existent dir: tc-testing
-Skipping non-existent dir: timens
-Skipping non-existent dir: timers
-Skipping non-existent dir: tmpfs
+Emit Tests for timens
+Emit Tests for timers
+Emit Tests for tmpfs
 Emit Tests for tpm2
 Emit Tests for user
 Skipping non-existent dir: vm
 Skipping non-existent dir: x86
 Emit Tests for zram
 chmod u+x /root/build/_kselftest_/run_kselftest.sh
-Created /root/build/_kselftest_/kselftest-packages/kselftest.tar.gz
+Created /root/build/_kselftest_/kselftest-packages/kselftest.tar.xz
 make: Leaving directory '/scratch/linux/tools/testing/selftests'

Also worth noting, the list of remaining directories being skipped with this PR (I guess non-arm64 directories are expected since this is an arm64 build, and bpf requires clang):

Skipping non-existent dir: bpf
Skipping non-existent dir: exec
Skipping non-existent dir: filesystems/binderfs
Skipping non-existent dir: kexec
Skipping non-existent dir: kvm
Skipping non-existent dir: pidfd
Skipping non-existent dir: powerpc
Skipping non-existent dir: sparc64
Skipping non-existent dir: tc-testing
Skipping non-existent dir: vm
Skipping non-existent dir: x86

So the list of extra directories that we might also be able to build with gcc are:

Skipping non-existent dir: exec
Skipping non-existent dir: filesystems/binderfs
Skipping non-existent dir: kexec
Skipping non-existent dir: kvm
Skipping non-existent dir: pidfd
Skipping non-existent dir: tc-testing
Skipping non-existent dir: vm

[gctucker]

Full build log with this PR applied:
https://storage.staging.kernelci.org/kernelci/staging.kernelci.org/staging-20200916.4/arm64/defconfig+kselftest/gcc-8/build.log

[alexandrasp]

Small changes, but big impact. :)