Support MSP430 architecture and target

[alexchandel]

The MSP430 architecture is a common target in embedded programming, namely TI's MSP430 microcontroller family, and should be targetable by Rust. Support for MSP430 was recently added to LLVM, although absent LLD support the MSP430 binutils is still necessary (as for all platforms). Previously, the only way to target MSP430 was using the custom GCC toolchain.

[alexchandel]

Interestingly, compiling bare-bones Rust to IR, then compiling to MSP430 assembly with LLVM master, then assembling/linking with the GCC toolchain, succeeds.

[torrancew]

👍 msp430 support would be fantastic

[steveklabnik]

I'm pulling a massive triage effort to get us ready for 1.0. As part of this, I'm moving stuff that's wishlist-like to the RFCs repo, as that's where major new things should get discussed/prioritized.

This issue has been moved to the RFCs repo: rust-lang/rfcs#758