Draft: Fix building on non RISC OS 64 bit systems
Hello,
I have patched ROMUnjoin so that it may be compiled for amd64, outside of RISC OS.
- Source is now complete when __riscos define is set.
- Pointer arithmetic no longer assumes pointers fit into an int.
- Compiler warnings fixed (for gcc 11.3.0.)
I'm fairly confident that building under RISC OS with Norcroft will be unaffected, but I no longer have such a thing to hand to test with.