It looks like I'm doing sloppy work, today.

Another revised version, with 2 small changes:
  - The pre-processor condition used to determine whether we need to
    declare readlink in gdb_readlink.h or not was wrong. Somehow,
    HAVE_ macros and HAVE_DECL_ macros are handled differently.
  - I forgot to update hostio.c's dependency on gdb_readlink.h
    in the Makefile.

Both issues now fixed, and new patch attached.

I'm going to stop here for the day.

-- 
Joel