Refer to LINUX_KARCH instead of ARCH when bundling DTS files in the image
builder tarball.

While we're at it, also dereference symbolic links when copying as some
kernel architectures contain symbolic links in their DTS directories.

This fixes aarch64 imagebuilders such as brcm2708/bcm2710 ones in particular
as the kernel refers to "aarch64" as "arm64" internally.

Ref: https://forum.lede-project.org/t/lede-image-builder-problem/3680

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

This can be used to tweak the buildbot behavior without having to change
buildbot's configuration.
It will also allow us to add more aggressive clean steps (e.g. on
toolchain changes), which would break developers' workflows if enable
by default.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

The name "Plat'Home OpenBlocks AX3" causes the imagebuilders "make info"
command to fail with:

    bash: -c: line 0: syntax error near unexpected token `('
    bash: -c: line 0: `echo;  [...]'
    Makefile:99: recipe for target '_call_info' failed

Properly escape single quotes to avoid breaking the echo commands.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

Reduces tarball size and improves build time

Signed-off-by: Felix Fietkau <nbd@nbd.name>

Reduces tarball size and improves build time

Signed-off-by: Felix Fietkau <nbd@nbd.name>

Rework the bundle-libraries.sh implementation to use a more robust approach
for executing host binaries through the shipped ELF loader and libraries.

The previous approach relied on symlinks pointing to a wrapper script which
caused various issues, especially with multicall binaries as the original
argv[0] name was not preserved through the ld.so invocation. Another down-
side was the fact that the actual binaries got moved into another directory
which caused executables to fail looking up resources with paths relative
to the executable location.

The new library wrapper implements the following improvements:

 - Instead of symlinks pointing to a common wrapper, each ELF executable
   is now replaced by a unqiue shell script which retains the original
   program name getting called

 - Instead of letting ld.so invoke the ELF executable directly, launch
   the final ELF binary through a helper program which fixes up the argv[0]
   argument for the target program

 - Support sharing a common location for the bundled libraries instead of
   having one copy in each directory containing wrapped binaries

Finally modify the SDK build to wrap the staging_dir and toolchain binaries
which allows to use the SDK on systems with a different glibc version.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

Switch to xz compression instead of using bz2.
Saves about 20% of total size (ar71xx)

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

With symlink tree some directories are just symlinked which
means IB and SDK end up with a symlink instead of an actual
directory; this fixes the missing files by dereferencesing
the directories instead of copying the symlinks.

Signed-off-by: Daniel Dickinson <lede@cshore.thecshore.com>

Add a new "checksum" make target which generates an sha256sums file over the
image files produced in bin/targets/ and automatically call it during make
world after the package index generation.

The advantage of this new target is that it is guaranteed to run after the
images, the SDK and the ImageBuilder archives have been generated to ensure
that they all end up in the checksum file. Fixes FS#51.

Uses sed to postprocess the OpenSSL digest output into an sha256sum command
compatible format.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

Signed-off-by: Felix Fietkau <nbd@nbd.name>