endianness compile fixes
kernel: compact utility functions
vm: add third-party mmap() mode and PROCCTL

these two functions will be used to support all exec() functionality
going into a single library shared by RS and VFS and exec() knowledge
leaving VM.

	. third-party mmap: allow certain processes (VFS, RS) to
	  do mmap() on behalf of another process
	. PROCCTL: used to free and clear a process' address space
drop aout support

justification: soon we won't be able to execute sep I&D aouts at
all (because of the vanishing segments), which was the default mode
to generate them so most binaries will be sep I&D.

this makes the vfs/rs exec() unification work simpler.

after unification, common I&D aout could be added back quite simply.
exec() cleanup, generalization, improvement

	. make exec() callers (i.e. vfs and rs) determine the
	  memory layout by explicitly reserving regions using
	  mmap() calls on behalf of the exec()ing process,
	  i.e. handling all of the exec logic, thereby eliminating
	  all special exec() knowledge from VM.
	. the new procedure is: clear the exec()ing process
	  first, then call third-party mmap()s to reserve memory, then
	  copy the executable file section contents in, all using callbacks
	  tailored to the caller's way of starting an executable
	. i.e. no more explicit EXEC_NEWMEM-style calls in PM or VM
	  as with rigid 2-section arguments
	. this naturally allows generalizing exec() by simply loading
	  all ELF sections
	. drop/merge of lots of duplicate exec() code into libexec
	. not copying the code sections to vfs and into the executable
	  again is a measurable performance improvement (about 3.3% faster
	  for 'make' in src/servers/)
further libexec generalization

	. new mode for sys_memset: include process so memset can be
	  done in physical or virtual address space.
	. add a mode to mmap() that lets a process allocate uninitialized
	  memory.
	. this allows an exec()er (RS, VFS, etc.) to request uninitialized
	  memory from VM and selectively clear the ranges that don't come
	  from a file, leaving no uninitialized memory left for the process
	  to see.
	. use callbacks for clearing the process, clearing memory in the
	  process, and copying into the process; so that the libexec code
	  can be used from rs, vfs, and in the future, kernel (to load vm)
	  and vm (to load boot-time processes)
pm: ignore notify() from unknown sender

	. avoids annoying error message if e.g. buggy drivers
	  send pm notify()s that pm tries to reply() ENOSYS to
dumpcore: use ptrace function to trigger a coredump

	. dumpcore currently relies on minix segments
	. also ptrace dumpcore fix
drop segment from safecopy invocations

	. all invocations were S or D, so can safely be dropped
	  to prepare for the segmentless world
	. still assign D to the SCP_SEG field in the message
	  to make previous kernels usable
Move setjmp and strnlen to common/lib.

Move setjmp and strnlen to common/lib to allow libddekit to use them.
Upgrade libddekit and introduce devmand.

Devmand (Device manager daemon) is the daemon that will
dynamically manage services based on events received from
the system.
Add support in devmand for using config dirs.

Add support in devmand for using configuration directories to
allow 3rd party packages to add configuration items.
Add devmand configuration to /etc.
Add hot plugging infrastructure in rc file.

Adding hot plugging infrastructure in rc file. This includes
starting the devman service, mounting it's file system and
starting the corresponding devmand daemon.

This patch also provide error free shutdown of the USB sub-system.

The USB sub system needs to be shutdown in a certain order but also
consists of components living in /usr/pkg/. By checking the
existence of usbd we can stop it in the correct order.
drop segments from safemap/safeunmap invocations
drop from segments physcopy/vircopy invocations

	. sys_vircopy always uses D for both src and dst
	. sys_physcopy uses PHYS_SEG if and only if corresponding
	  endpoint is NONE, so we can derive the mode (PHYS_SEG or D)
	  from the endpoint arg in the kernel, dropping the seg args
	. fields in msg still filled in for backwards compatability,
	  using same NONE-logic in the library
Create cc symlink to clang
Let the kernel load figure out where to put mods

This patch makes the mkimage tool obsolete
Make commands cross-compilable
Make TTY cross-compilable