Now that the necessary functions from log.h have been moved to macro.h,
we can stop including log.h in macro.h. This requires modifying source
files all over the tree to include log.h instead.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
This adds a bit of generic helper tools for installing files/dir trees.
"installing" is supposed to mean the final step when preparing a disk
image or directory tree, where the result is renamed to its final name.
It has some bells and whistles, as it is able to replace existing files
sanely, can fsync() things carefully and can mark things read-only in a
nice way.
This is supposed to be generic, unified code that can be used eventually
for any of our tools that prepare disk images/directory trees, including
importd, nspawn's --template= mechanism, the discover-image.c logic,
and more.