jemalloc/jemalloc — pull request #106 by sgolemon (2014-08-18 20:28:42+00:00)
Title: Test for availability of malloc hooks via autoconf

__*_hook() is glibc, but on at least one glibc platform (homebrew),
the __GLIBC__ define isn't set correctly and we miss being able to
use these hooks.

Do a feature test for it during configuration so that we enable it
anywhere the hooks are actually available.