unexec is only done once, at build-time, to convert temacs with a bunch of loaded libraries to emacs, which includes those libraries already. So it doesn't need to search them on disc, and compile them.
It's never serialized. It's just dumped. Like a core file, with just proper headers, sections and segments, so that it can be executed. A proper COFF/ELF binary. A core file has all the segments but misses the headers.
Ok, so why can't it just be dumped to a .S file, so the regular toolchain can handle creating the headers, sections, and segments? .S files basically let you create arbitrary ELF images without making you implement the ELF format yourself. I'm really not getting what the custom linker/toolchain in unexec is buying you.
It's never serialized. It's just dumped. Like a core file, with just proper headers, sections and segments, so that it can be executed. A proper COFF/ELF binary. A core file has all the segments but misses the headers.