Titles pass handle 0 (RTLD_DEFAULT) for a process-wide lookup, and the loader rejected it: the handle is
not in the module map, so every such lookup failed even when a loaded module exports the symbol. Handle 0
and -2 now take the default scope, searching the global modules by plain name, NID and `#guest` form, and
then the process-wide scope.
The process-wide scope of the real loader also contains glibc and libstdc++, so an unfiltered fallback
would answer `malloc`, `dlopen` and `pthread_create` where PS5 reports the symbol as missing: handle 0 is
the main program, whose lookup sees the program's exports, not the host C++ runtime. A result from the
process scope is therefore accepted only when `dladdr` attributes it to a converted or replacement module
(a `.prx` library or the executable), which keeps the fallback for guest symbols and removes the host
leak. `guest_dynamic_loader` asserts the three host names are not found; disabling the filter makes that
test fail.
The scripting heap that an earlier revision of this branch added has been dropped: the title reaches the
same boot milestone with the lookup failing honestly, so the export was an inference rather than a
requirement, and prosper's bring-up notes report `ESRCH` for that name on hardware.