No threading yet, so no real locking

This forces the linker to add a DYNAMIC segment, allowing us to export our
symbols to loaded libraries.

This gives us full control over linker options.

We need the headers so we can provide the symbols to loaded libraries.
This means we cannot use objcopy to munge the binary format to elf32-i386,
as the loader doesn't understand this format.

Instead, add a separate 32-bit only stage (in elf32-i386 format) that loads
the 64-bit image into memory as its payload.  This keeps multiboot happy and
leave our headers alone.

Set up 32-bit entry point via linker script.

Add a Makefile and a main function around which the loader will be built.