Improved build-time unsigned modules detection
Fixed lid-close events matching
Differentiated between "lost" and readonly boot media

Boot media can become "lost" when it is not recognized as USB 2.0
during early boot (due to missing modules), and is recognized as
such later, in which case, e.g., /dev/sdb disappears and is replaced
with /dev/sdc, while /mnt/boot is still reported as a mountpoint
with a non-existing /dev/block/major:minor device.

This is useful for bug reporting.
Improved initramfs device drivers coverage

This fixes issues such as not detecting USB drives as USB 2.0,
and later "losing" the device later during the boot process.
Added "gentoo=nontp" boot parameter for disabling NTP
Added build-time kernel modules signatures verification
Added "tz" boot parameter for RTC timezone specification

tz=<timezone> or tz=:<timezone> boot parameter now sets
a corresponding TZ environment variable for "init" (pid=1) process,
which is then propagated further down the chain, since it is now
in OpenRC's "rc_env_allow". This is useful in tandem with "nontp"
boot option and non-UTC RTC.

Environment is now sanitized before running "init" -- only
TZ and/or TERM are passed through.

Removed default TZ=:UTC setting in main user and root's environment,
in order to use tz=<timezone> override if locale has not been
customized.
Added sys-apps/gptfdisk (gdisk) package

gdisk is necessary to allow self-installation to GPT disks.
Added support for exFAT filesystem

exFAT is currently supported via a FUSE module.