We seem to run into trouble with regular glibc malloc on Linux, so use
jemalloc instead of glibc's malloc.

This can be disabled using --disable-jemalloc


git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@3216 d4fa192b-c00b-0410-8231-f00ffab90ce4