and ok jeremy@

no longer has access to the content of a memmory object. It does
this by either clearing (if the object memory remains cached) or
by calling munmap(2). ok millert@, deraadt@, guenther@

ok deraadt@

detected wrt recallocarray()

ok jmc@ deraadt@

from David CARLIER

never occur

- use internal meta-data to do more consistency checking (especially with
option C)
- use cheap free if possible
ok deraadt@

make the behaviour -> use case connection.
help from jmc and jsing

help and ok from tom@ and deraadt@

with the added feature that released memory is cleared. Much input from various
developers. ok deraadt@ tom@

free() error path.
ok otto@

a page.  This is not required by any standard and other malloc
implementation do not document (or implement) this. ok deraadt@

half a page and a page. ok jmatthew@ tb@

allocation to the size of the new allocation (instead of the requested size).
2. Previously realloc takes the easy way and always reallocates if C is
active. This commit fixes by carefully updating the recorded requested
size in all cases, and writing the canary bytes in the proper location
after reallocating.
3. Introduce defines to test if MALLOC_MOVE should be done and to
compute the new value.

This is a remnant from the original 4.4BSD code that had 'a' as
void * in the function args.  No binary change.  OK bluhm@

been the default for ages, and I see no valid reason to be able to
disable it. ok natano@

quickly. In both cases it does not make sense to set hints on them.
So remove that option, which is just a remainder of old times when
malloc used to hold on to pages. ok stefan@

- redundant cast is redundant

prodded by otto@
ok kettenis@ otto@

recomputing it all the time

instead of chunk itself; does not change actual allocated size; ok tedu@

or prototypes.  Ditto for some of the char* and void* casts too.
verified no change to instructions on ILP32 (i386) and LP64 (amd64)
ok natano@ abluhm@ deraadt@ millert@

ok tedu@