Add mmap usage in malloc_info output

The current malloc_info xml output only has information about
allocations on the heap.  Display information about number of mappings
and total mmapped size to this to complete the picture.
Fix formatting in malloc_info
Replace __int128 with __int128_t

	* sysdeps/x86_64/link-defines.sym (BND_SIZE): Replace __int128
	with __int128_t.