* dll_init.cc (reserve_upto): Remove.

* dll_init.cc (reserve_upto): Remove.
(release_upto): Ditto.
(dll_list::reserve_space): New function to reserve space needed by DLL_LOAD
dlls early in the fork process.
(dll_list::load_after_fork): Rewrite to use recursion for tracking reservations
made while trying to make dlls land where they belong.
(dll_list::load_after_fork_impl): Ditto.
(dll_list::alloc): Initialize image base field.
* dll_init.h (struct dll_list): declare new functions.
(dll::image_size): New member.