vm: replace phys avl by array

 . make vm be able to use malloc() by overriding brk()
   and minix_mmap() functions
 . phys regions can then be malloc()ed and free()d instead
   of being in an avl tree, which is slightly faster
 . 'offset' field in phys_region can go too (offset is implied
   by position in array) but leads to bigger code changes
kernel debug: priv can be NULL early on
kernel: vm kernel call can't suspend
include: reduce default stack size
libexec exec fix

	. restores executing shell scripts without explicit interpreter
unstack: add shared libraries symbols
unstack - fix ipcvecs
vm: Fix sparepage resource leak.

Fix a sparepage resource leak by preventing to call
vm_getsparepage twice.

Change-Id: I06557d47b90a7cca74e0a86921c2579f9618685d
vfs:fix for variable 'rfp' set but not used.

mount.c: In function 'mount_pfs':
mount.c:395:17: error: variable 'rfp' set but not used [-Werror=unused-but-set-variable]

Change-Id: I2f22590ab4e3a4a1678e9096626ebca53d2660e6
kernel: restore stacktraces

When processes have entered the kernel with one of the new
trap modes, %ebp is not valid, used for stacktraces, so we
need an alternative way to retrieve it to make the stacktraces
valid again.
test:update tests to fix compiler warnings.

Change-Id: Id2c757f61fe5e8b52dffadfeb129024625c76f48
vm:enable the instruction and data caches.

Enable the instruction and data caches. Whether data is cached
will depend on the MMU entries.

Change-Id: I51e9ebc38924db5525d4e7ad9ab69b2a5b1ca7b4
kernel:add a some information in backtraces.

* Display the pid and process name in the backtrace as we can
currently not read stackframes.

Change-Id: I2435d4098553c5b02adfe36f08b5aa3f47e9b531
kernel: restore setting KTS_NONE

The 'trap style' variable records how a process has trapped into the
kernel (hardware/software interrupt, or one of the other trap
instructions). KTS_NONE indicates the process isn't trapped into the
kernel at all and is useful for sanity checking. The KTS_NONE reset was
inadvertently removed while removing some debugging code and this commit
restores it.
kernel: separate state for trace-deferred syscalls

state is usually not in p_reg any more with sysenter/syscall trap entries,
so when saving/restarting do_ipc invocations the state has to be remembered
explicitly.
vm: restore stacktrace on SIGSEGV
kernel: trap-dependent state restore, trace fixes

	. restore state depends on how saving of state was done;
	  also remember trap style in sig context
	. actually set and restore TRACEBIT with new trap styles;
	  have to remove it once process enters kernel though, done
	  in debug trap exception handler
	. introduce MF_STEP that makes arch-specific code
	  turn on trace bit instead of setting TRACEBIT directly,
	  a bit more arch-friendly and avoids keeping precious
	  state in per-process PSW arch-dependently
libc, libutil: remove compat hacks
gzip: fix warning messages with off_t

NetBSD assumes off_t is 64-bit, but on MINIX it is still 32-bit.
So cast the calls to use big_off_t, as stat(2) uses.
Only used in warning messages, was not a real production bug.
Drop obsolete klib16.S

The 16-bit poweroff16() function is not called any more.