over EFence and also hopefully smaller memory overhead, but sadly it's non-free
for commercial use).
If the DMALLOC_OPTIONS environment variable is not set, switch on `reasonable'
checks by default.
Also introduced mb_allocz() for cleared mb_alloc().
- cfg_strcpy() -> cfg_strdup()
- mempool -> linpool, mp_* -> lp_* [to avoid confusion with memblock, mb_*]
Anyway, it might be better to stop ranting about names and do some *real* work.
