* Added x86_64 linker script and relocation code.
* Some 64-bit safety fixes to the heap code.
* Added runtime_loader, libroot and bash to the x86_64 image. The boot
script will be launched, but will panic shortly after because fork
is broken.
Added a temporary Haiku64Image file that gets included instead of
HaikuImage when building for x86_64, which I will add to as I port
stuff. Images currently only include the boot loader, kernel and
a bunch of add-ons.
