Rename current-os-name, current-processor-name.

current-os-name => target-os-name
current-processor-name => target-architecture-name

This makes it clear that the values describe the compilation target
and not the properties of the system running the compiler.
[llvm rtg] Use architecture instead of processor.
Refer to architecture, not processor.

Trying to make the internal terminology consistent.
Merge pull request #465 from waywardmonkeys/rename-current-target

Use consistent terminology