build failure with rust stable toolchain

building with nightly-2021-01-01-x86_64-unknown-linux-gnu succeeds, so it may be that you simply need to add a rust-toolchain file until the required features are in stable.

this is the error with stable:

$ cargo build --release
[...]
error[E0658]: platform intrinsics are experimental and possibly buggy
  --> /home/khimaros/.cargo/registry/src/github.com-1ecc6299db9ec823/vek-0.12.1/src/simd_llvm.rs:13:8
   |
13 | extern "platform-intrinsic" {
   |        ^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #27731 <https://github.com/rust-lang/rust/issues/27731> for more information

error[E0554]: `#![feature]` may not be used on the stable release channel
 --> /home/khimaros/.cargo/registry/src/github.com-1ecc6299db9ec823/slotmap-0.4.0/src/lib.rs:4:35
  |
4 | #![cfg_attr(feature = "unstable", feature(untagged_unions, try_reserve))]
  |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0554`.
error: could not compile `slotmap`

zesterer / teloren

build failure with rust stable toolchain #5