Replace `rustc_target::specTarget::arch` string with enum (original) (raw)

Proposal

I propose to replace the stringly-typed Target::arch: Cow<'static, str> with a new Architecture enum. The work is already done.

The change is mechanical but large, and this MCP is filed per @nnethercote's request.

The main points of the Major Change Process are as follows:

File an issue describing the proposal.
A compiler team member who is knowledgeable in the area can second by writing @rustbot second or kickoff a team FCP with @rfcbot fcp $RESOLUTION.
- Refer to Proposals, Approvals and Stabilization docs for when a second is sufficient, or when a full team FCP is required.
Once an MCP is seconded, the Final Comment Period begins.
- Final Comment Period lasts for 10 days after all outstanding concerns are solved.
- Outstanding concerns will block the Final Comment Period from finishing. Once all concerns are resolved, the 10 day countdown is restarted.
- If no concerns are raised after 10 days since the resolution of the last outstanding concern, the MCP is considered approved.