Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Merge from CheriBSD:

Make the sysinit tool a build tool rather than building in with
/usr/bin/cc and running it from OBJDIR. (It will be moved to usr.bin
once a manpage is written and a few style cleanups are done.)

Split the makefile bits for Hans' kernel shim layer into their own
includable kshim.mk.

Move USB support into a .mk file so loaders can include it.

Use own memory pool of 128K until further, hence that works the best.

Sponsored by: DARPA, AFRL

USB boot library improvements:
- Make the USB boot library more configurable.
- Resolve compile issues when cross building.
- Allow use of separate malloc.
- Allow use of separate endian macros.

Sponsored by: DARPA, AFRL

For libstand and sys/boot, split off gcc-only flags into CFLAGS.gcc.

MFC after: 3 days
X-MFC-With: r259730

Fix depend target.

Initial version of libusbboot, a fully stand-alone, single threaded and
functional compilation of the FreeBSD USB stack for use with boot loaders
and such.

Discussed with: Hiroki Sato, hrs @ EuroBSDCon