- Get rid of preprocessor override of kernel malloc API names.  This
  is no longer necessary with the UHI approach, and creates problems
  when incorporating other kernel code that uses the preprocessor to
  override malloc names (e.g., libalias).

- arc4random() reimplementation should be in UHI, so now it is.

- Objects calling into host OS APIs should not be part of the prelink
  stage when building libuinet, as this risks resolving host API names
  using libuinet kernel names.  The host objects are now linked into
  the library after the prelink/symbol hiding step is complete.