* Update to nightly-2020-12-11.
* Update for rustfmt changes (`cargo fmt --all`).
* Update `rustc_codegen_spirv::linker::test` for `rustc_interface` changes.
* Use `spirv_tools::util::{to,from}_binary` to pacify clippy.
* `#[allow(clippy::unnecessary_wraps)]` on `Result`-returning `fn run_thin`.
* Generalize the zombie serialization system to arbitrary custom decorations.
* Support "Unroll" Loop Control via function-scoped `#[spirv(unroll_loops)]`.
* Pacify the merciless clippy.
* Get closer to testing NO_DCE in CI
The only remaining validation issues are due to the SROA pass not being
implemented yet
* Revert mistakenly included change
* new_structurizer: fix infinite loops.
* intrinsics: use an infinite loop for `abort`.
* Don't deduplicate zombie values even with other zombies.
* Bring back `zombie_even_in_user_code` and use it for constants.
* Use global `OpVariable`s instead of undefs for `ConstantPointer`s.
* Intercept panic calls and replace them with aborts.
* Update DILocation and update trait impls for nightly
* rustc_codegen_spirv: Update mir Scalar handling to nightly 2020-11-04
3a7970848cdf4d717d0b
* More changes to compile on the latest nightly
* Remove unused import warnings
Co-authored-by: Marijn Suijten <marijns95@gmail.com>
