mrc.bin is now handled by include/mrc.sh, adapted
from now-deleted script/update/blobs/mrc

much of the logic has been re-written or adapted for
inside script/update/blobs/download

mrc links/hashes now defined in config/blobs/sources

the new code is simpler (and smaller). in addition,
lbmk can now easily handle mrc.bin files for other
platforms such as broadwell. watch this space.

the full .zip download is now cached, like with other
vendor downloads. this means it won't be re-downloaded
if it was already downloaded before.

Signed-off-by: Leah Rowe <leah@libreboot.org>

Use the same logic between blobs/download and blobs/mrc.

The logic is taken from blobs/download.

Signed-off-by: Leah Rowe <leah@libreboot.org>

This results in much cleaner copyright and license declarations.
SPDX headers are legally recognised and make auditing easier.

Also, remove descriptions of each script, from each script.
Libreboot documentation at docs/maintain/ describes them.

Signed-off-by: Leah Rowe <leah@libreboot.org>

there were a few missing err calls

i actually went through all of lbmk and found no
instances where err calls were missing except in
build/boot/roms_helper

Signed-off-by: Leah Rowe <leah@libreboot.org>

in some cases, messages that should be considered errors
or warnings, were being written to the standard output,
rather than written as error messages.

also: one or two printf statements should specifically
avoid printing errors (to any file); in these cases,
stdout has been redirected to /dev/null

Signed-off-by: Leah Rowe <leah@libreboot.org>

sha-1 has known collision issues, which may not be readily
exploitable yet (in our context), but we should ideally use
a more secure method for checking file integrity.

therefore, use sha-2 (sha512sum) for checking files. this is
slower than sha-1, but checksum verification is only a minor
part of what lbmk does, so the overall effect on build times
is quite negligible.

Signed-off-by: Leah Rowe <leah@libreboot.org>

explicitly set the count to 3, so that a maximum of 3
attemps are made per download, barring fatal errors such
as http 404.

Signed-off-by: Leah Rowe <leah@libreboot.org>

this means the unified /tmp handling is now provided for
in both the former "fetch" and "fetch_trees" script, which
are now (respectively):

./update project repo
./update project trees

if the fetch scripts weren't cleaning /tmp before, they
now are, because lbmk handles it

Signed-off-by: Leah Rowe <leah@libreboot.org>

Signed-off-by: Leah Rowe <leah@libreboot.org>