much, much stricter, more verbose error handling

lbmk is much more likely to crash now, in error conditions,
which is a boon for further auditing.

also: in "fetch", remove the downloaded program
if fail() was called.

this would also be done for gnulib, when downloading
grub, but done in such a way that gnulib goes first.

where calls to err write "ERROR" in the string, they
no longer say "ERROR" because the "err" function itself
now does that automatically.

also: listmodes/listoptions (in "lbmk") now reports an
error if no scripts and/or directories are found.

also: where a warning is given, but not an error, i've
gone through in some places and redirected the output
to stderr, not stdout

as part of error checks: running anything as root, except
for the "./build dependencies *" commands, is no longer
permitted and lbmk will throw an error

mrc downloads: debugfs output no longer redirected to /dev/null,
and stderr no longer redirected to stdout. everything is verbose.

certain non-error states are also more verbose. for example,
patch_rom in blobs/inject will now state when injection succeeds

certain actual errors(bugs) were fixed:
for example, build/release/roms now correctly prepares the blobs
hash files for a given target, containing only the files and
checksums in the list. Previously, a printf message was included.
Now, with this new code: blobutil/inject rightly verifies hashes.

doing all of this in one giant patch is cleaner
than 100 patches changing each file. even this is yet part
of a much larger audit going on in the Libreboot project.

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

.gitcheck

@@ -10,6 +10,8 @@ git_email="placeholder@lbmkplaceholder.com"
 
 main()
 {
+	[ "$(id -u)" = "0" ] && return 0
+
 	if [ $# -gt 0 ]; then
 		if [ "${1}" = "clean" ]; then
 			clean 1> /dev/null