Since we're now including jemalloc_internal.h, all the required headers
are already pulled. This will avoid having to fiddle with headers that can
or can't be used with MSVC. Also, now that we use malloc_printf, we can use
util.h's definition of assert instead of assert.h's.

Commit 4eeb52f0 removed vsnprintf validation, but left a now unused va_copy.
It so happens that MSVC doesn't support va_copy.

Remove mmap_unaligned, which was used to heuristically decide whether to
optimistically call mmap() in such a way that could reduce the total
number of system calls.  If I remember correctly, the intention of
mmap_unaligned was to avoid always executing the slow path in the
presence of ASLR.  However, that reasoning seems to have been based on a
flawed understanding of how ASLR actually works.  Although ASLR
apparently causes mmap() to ignore address requests, it does not cause
total placement randomness, so there is a reasonable expectation that
iterative mmap() calls will start returning chunk-aligned mappings once
the first chunk has been properly aligned.

Fix chunk_alloc_dss() to zero memory when requested.

Fix chunk_dealloc() to avoid chunk_dealloc_mmap() for dss-allocated
memory.

Fix huge_palloc() to always junk fill when requested.

Improve chunk_recycle() to report that memory is zeroed as a side effect
of pages_purge().

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.