MFC r233307:

MFC r233307:
Use xmalloc() instead of malloc() in the places where malloc() calls
are assumed to not fail.

Make the xcalloc() calling conventions follow the calloc(3) calling
conventions and replace unchecked calls to calloc() with calls to
xcalloc().

Remove redundand declarations from xmalloc.c, which are already
present in rtld.h.

git-svn-id: svn://svn.freebsd.org/base/stable/9@233922 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f