BUILD: makefile: enable both DEBUG_STRICT and DEBUG_MEMORY_POOLS by default

BUILD: makefile: enable both DEBUG_STRICT and DEBUG_MEMORY_POOLS by default

The first one will enable all currently deployed BUG_ON() checks. These
ones are safe from a performance perspective and from a reliability
perspective. New ones may be added later with different categories
(hot path, detection of uncertain events, etc).

DEBUG_MEMORY_POOLS enables the "tag" pool debugging option by default,
so that pools may be better traced in dumps. This one alone results in
almost imperceptible performance difference, and 8 extra bytes per
allocated object.

Both options are safe for production use (they're among those enabled
all the time on haproxy.org) and allow to produce much more trustable
bug reports which should save a few round trips with the reporters.