MEDIUM: pools: respect pool alignment in allocations

MEDIUM: pools: respect pool alignment in allocations

Now pool_alloc_area() takes the alignment in argument and makes use
of ha_aligned_malloc() instead of malloc(). pool_alloc_area_uaf()
simply applies the alignment before returning the mapped area. The
pool_free() functionn calls ha_aligned_free() so as to permit to use
a specific API for aligned alloc/free like mingw requires.

Note that it's possible to see warnings about mismatching sized
during pool_free() since we know both the pool and the type. In
pool_free, adding just this is sufficient to detect potential
offenders:

	WARN_ON(__alignof__(*__ptr) > pool->align);