no need to save the stack pointer. Just push the space for the cleanup
and obj_main pointers before calling _rtld(), and pop it after loading those
pointers into the appropriate argument registers for the program entry point.
kit, then hacked on by Matt Thomas <matt@3am-software.com>, then by me (to
make it work with new versions of the toolchain, etc.). This runs, but it's
in serious need of cleaning and/or a fair bit of reworking. See the README
file for more information, and a list of things to do.