Almost all the headers in cryptsetup are self-suffienct (in that they
compile on their own). By including <stddef.h>, <stdint.h>, or
<sys/types.h>, all headers will now compile on their own.
This is useful for importing cryptsetup into Bazel/Blaze.
Code is written by Ondrej Kozina.
This patch adds ability to store volume key in kernel keyring
(feature available in recent kernels) and avoid setting
key through dm-ioctl and avoiding key in table mapping.
Will be used in LUKS2.
Signed-off-by: Milan Broz <gmazyland@gmail.com>
