Add the posix_memalign(3) function to bionic

The posix_memalign(3) function is very similar to the traditional
memalign(3) function, but with better error reporting and a guarantee
that the memory it allocates can be freed.  In bionic, memalign(3)
allocated memory can be freed, so posix_memalign(3) is just a wrapper
around memalign(3).

Change-Id: I62ee908aa5ba6b887d8446a00d8298d080a6a299
2 files changed