patch from psm:

patch from psm:
- malloc/realloc/free are not prepared to be hidable in trunk, you can't
  use libc_hidden_proto(x) for them
- using libc_hidden_proto(x64) LFS unguarded will fail because the header
  does not provide the prototype
- if you are using libc_hidden_proto(collated_compare|prefix_array), you
  also need libc_hidden_def|_weak(x) after the function itself, the result
  being to provide a hidden __GI_collated_compare and a visible
  collated_compare, for this case I do not consider this necessary,
  especially that collated_compare is hidden already (I have chosen to
  prefix them with __ to know that they are intended to be internal only,
  against the practice in glibc, you could go without prefix as well)