pigz(1) is a parallel gzip implementation. As such, it significantly
faster than gzip(1). This patch uses pigz(1) instead of gzip(1),
if it is installed, otherwise it just falls back to gzip(1). This is
similar to the current pigz support in abuild.

Without this patch:

	$ time mkinitfs
	==> initramfs: creating /boot/initramfs-lts
	real	0m 38.19s
	user	0m 35.47s
	sys	0m 0.49s

With this patch applied and pigz installed:

	==> initramfs: creating /boot/initramfs-lts
	real	0m 13.24s
	user	0m 38.30s
	sys	0m 0.56s

This change was discussed on IRC with _ikke_ and mps.

The LUKS2 cryptsetup format uses a locking mechanism, see the "LUKS2
header locking" section in cryptsetup(8) for further information on this
mechanism. The mechanism requires a locking directory, if it is not
present it will be created automatically. Unfortunately, cryptsetup
emits a warning when creating it.

To silence this warning message make init create the directory.

Without this change this may result in a warning message to be printed
during boot if the rootfstype kernel parameter is not set.

ref https://gitlab.alpinelinux.org/alpine/aports/issues/11044

Add new feature rpi rtc allowing a hw rtc to be used.

The init script in Alpine Linux since v3.9 looks for /dev/rtc, if
not found it will switch to swclock.

To make this check work on a Rasberry PI with a mounted rtc and
the following in usercfg.txt
 dtoverlay=i2c-rtc,ds3231
we must have rtc drivers available already initramfs.