core.runtime.GC memory alignment

[David Nadlinger]

The documentation for the GC.malloc family of functions mentions 
that they return "an aligned block of managed memory from the 
garbage collector" without any further specification about what 
that level of alignment is supposed to be.

What do we actually want to guarantee here? "Sufficient for any 
built-in type"?

Note that my question is not about how the current implementation 
behaves, but about what the actual API guarantee should be.

David