Overwrite the OSX default zone allocator, taking into account the malloc_zone_t
version (supported versions are 3, 6, and 8) for Leopard, Snow Leopard and
Lion. jemalloc can be dynamically disabled for unknown malloc_zone_t versions,
for OSX 10.8 and beyond.
The changeset does not enable jemalloc, to allow for easy disabling if there's
a problem. It will be enabled in the next changeset.
This should be a 15-20% improvement in memory usage.
(transplanted from 098cf0d0c599fdcfedbc6ee5aadf01259e9dcd09)
--HG--
extra : transplant_source : %09%8C%F0%D0%C5%99%FD%CF%ED%BCn%E5%AA%DF%01%25%9E%9D%CD%09