cp (and potentially mkdir -p) are not atomic, and we have seen situations where two packages
concurrently copying the same file (eg. the udev rule for xf86-video-nvidia and
xf86-video-nvidia-legacy) will succeed for one package but the other package fails with
a "file exists" error (as the file didn't exist when it checked, but does exist when it
actually copies the file). Not even cp -f will avoid this issue.
There are several workarounds, but the most practical (and general) solution is to ensure
sequential updates of the image and shared sysroot directories.
With the upcoming usage of the standard install_pkg folder for addon
dependencies, the devel files need to be accessible, e.g. ffmpegx for
tvheadend.
So don't wipe them from the package install folder, just skip copying
them to the image.
More efficient, slightly more functional.
Can be a space delimited list of architectures.
Architectures to be excluded can be specified with !ARCH.
Allows "any !arm" to be interpreted as "any arch, but not arm".
Blank/undefined is equivalent to "any".
