I'm afraid there's not really any trivial solution for at least NetBSD and
OpenBSD that is not a gross hack. The problem is that the Objective-C runtime
system expects that it's class and method tables are initialized when a program
starts. In particular, for each compilation unit the compiler generates
implicit calls to _objc_exec_class that makes sure the class structures and
method dispatch tables are initialized for all classes used in that compilation
unit. This code is added to the init section of the object file. At runtime the
C startup code will execute all functions compiled into the init section.
Unfortunately, in a sort of paranoia (that I generally appreciate), the NetBSD
and OpenBSD startup code uses a flag in private memory to ensure that this code
is executed only once. The final Emacs executable is the result of dumping the
process with all essential modules loaded. Obviously, at that point the
initialization code has been run and the flag is set, so when you execute the
dumped emacs executable the initialization code is not run again. Now this
would actually make sense if the data structures generated by the Objective-C
runtime system were part of the dumped Emacs executable, but apparently they
are not.