Fix a memory corruption bug in chunk_alloc_dss() that was due to
claiming newly allocated memory is zeroed.

Reverse order of preference between mmap() and sbrk() to prefer mmap().

Clean up management of 'zero' parameter in chunk_alloc*().

Put CONF_HANDLE_*() keys in quotes, so that they aren't mangled when
--with-private-namespace is used.

Don't mangle pthread_create(); it's an exported symbol when defined.

Bookkeeping an extra argument that actually only stores a function pointer
for a function we already have is not very useful.

Using static memory when malloc_tsd_malloc fails means all threads share
the same wrapper and thus the same wrapped value. This defeats the purpose
of TSD.

Not setting the initialized member leads to randomly calling the cleanup
function in cases it shouldn't be called (and isn't called in other
implementations).

Make special FreeBSD libc/libthr function overrides for
_malloc_prefork(), _malloc_postfork(), and _malloc_thread_cleanup()
visible.

These flags take unsigned values, but they were fed with signed values
taken with va_arg, and that led to sign extension in cases where the
corresponding value has the most significant bit set.

This will be used to implement the feature on mingw, which doesn't have
madvise.

This allows for different patterns for file names:
- lib.so.version for e.g. Linux
- lib.version.dylib for OSX (which is much more common than
lib.dylib.version)
- lib.dll for Windows (no version at all).

Clean up a few config-related conditionals to avoid unnecessary
dependencies on prof symbols.  Use cassert() rather than assert()
everywhere that it's appropriate.

Change the "opt.lg_prof_sample" default from 0 to 19 (1 B to 512 KiB).

Change the "opt.prof_accum" default from true to false.

Add the "opt.prof_final" mallctl, so that "opt.prof_prefix" need not be
abused to disable final profile dumping.

Add atomic(9) implementations of atomic operations.  These are used on
FreeBSD for non-x86 architectures.

This will make things easier for MSVC support.

This makes hacking on Makefile easier.

This avoids fork/exec()ing in loops, as echo is a builtin, and makes
size_classes.sh much faster (from > 10s to < 0.2s on mingw on my machine).

This will allow linking for win32 without pthreads more easily

It is a linker flag, so it doesn't make sense in CFLAGS, and it's the
default when invoking the linker for shared libraries.

Start preparing ChangeLog for 3.0.0 release.  Additional fixes and
changes are yet to come, so this is not a complete ChangeLog.

Add the --disable-munmap option, remove the configure test that
attempted to detect the VM allocation quirk known to exist on Linux
x86[_64], and make --disable-munmap implicit on Linux.

Add a configure test to determine whether common mmap()/munmap()
patterns cause VM map holes, and only use munmap() to discard unused
chunks if the problem does not exist.

Unify the chunk caching for mmap and dss.

Fix options processing to limit lg_chunk to be large enough that
redzones will always fit.

Always disable redzone by default, even when --enable-debug is
specified.  The memory overhead for redzones can be substantial, which
makes this feature something that should only be opted into.

test/bitmap.c #includes src/bitmap.c, which is correctly detected by gcc -MM,
but building test/bitmap.o doesn't require src/bitmap.o.

Chunk_boot0 calls rtree_new, which calls base_alloc, which locks the
base_mtx mutex. That mutex is initialized in base_boot.

Normalize arena_palloc(), chunk_alloc_mmap_slow(), and
chunk_recycle_dss() to use the same algorithm for trimming
over-allocation.

Add the ALIGNMENT_ADDR2BASE(), ALIGNMENT_ADDR2OFFSET(), and
ALIGNMENT_CEILING() macros, and use them where appropriate.

Remove the run_size_p parameter from sa2u().

Fix a potential deadlock in chunk_recycle_dss() that was introduced by
eae26903 (Add alignment support to
chunk_alloc()).

Implement Valgrind support, as well as the redzone and quarantine
features, which help Valgrind detect memory errors.  Redzones are only
implemented for small objects because the changes necessary to support
redzones around large and huge objects are complicated by in-place
reallocation, to the point that it isn't clear that the maintenance
burden is worth the incremental improvement to Valgrind support.

Merge arena_salloc() and arena_salloc_demote().

Refactor i[v]salloc() to expose the 'demote' option.

Rename labels from FOO to label_foo in order to avoid system macro
definitions, in particular OUT and ERROR on mingw.

Reported by Mike Hommey.