This version includes a few minor performance improvements in addition to the listed new features and bug fixes.

New features:

• Add clipping support to lg_chunk option processing.
• Add the --enable-ivsalloc option.
• Add the --without-export option.
• Add the --disable-zone-allocator option.

Bug fixes:

• Fix "arenas.extend" mallctl to output the number of arenas.
• Fix chunk_recycle() to unconditionally inform Valgrind that returned memory is undefined.
• Fix build break on FreeBSD related to alloca.h.