MFC r229848:

MFC r229848:

  Add aligned_alloc(3).

  The C11 folks reinvented the wheel by introducing an aligned version of
  malloc(3) called aligned_alloc(3), instead of posix_memalign(3). Instead
  of returning the allocation by reference, it returns the address, just
  like malloc(3).

I'm MFCing this now, as it seems aligned_alloc(3) is needed to make the
new version of libc++ work, which was merged back to FreeBSD 9 in r243376.

Requested by:	dim

git-svn-id: svn://svn.freebsd.org/base/stable/9@243405 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f