Add pahole during build

add pahole add-on during build to
allow kernel with BPF/BTF enabled
to be built. no need to install pahole
since we only need it during build.

the procedure to prepare pahole tar ball:

download pahole from [0]
untar it and download libbpf from [1]
and untar libbpf

then:

rm pahole-1.25/lib/bpf
mv libbpf-1.3.0 to pahole-1.25/lib/
cd pahole-1.25/lib/
mv libbpf-1.3.0 bpf
cd ../../
tar -czcf pahole-1.25.tar.gz pahole-1.25

mv pahole-1.25.tar.gz ipfire-2.x/cache
b2sum ipfire-2.x/cache/pahole-1.25.tar.gz

Note cmake without optimization -O2 in
lfs/pahole result in _FORTIFY_SOURCE requires
optimzation error since ipfire glibc built
with --enable-fortify-source

this also avoid the hack in [2]

[0]https://git.kernel.org/pub/scm/devel/pahole/pahole.git/snapshot/pahole-1.25.tar.gz
[1]https://github.com/libbpf/libbpf/archive/refs/tags/v1.3.0.tar.gz
[2]https://community.ipfire.org/t/how-to-customize-config-kernel-kernel-config-x86-64-ipfire/11100/8

Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>

make.sh

@@ -1128,6 +1128,7 @@ buildipfire() {
   lfsmake2 iproute2
   lfsmake2 screen
   lfsmake2 elfutils
+  lfsmake2 pahole
   lfsmake2 expat
   lfsmake2 libconfig
   lfsmake2 curl