Seems like feature selection is broken

[pedrocr]

I'm enabling this crate with:

#[runtime_target_feature("+avx2")]

This gives me:

warning: #[target_feature = ".."] is deprecated and will eventually be removed, use #[target_feature(enable = "..")] instead
  --> src/main.rs:17:1
   |
17 | #[runtime_target_feature("+avx2")]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

'++avx2' is not a recognized feature for this target (ignoring feature)
'++avx2' is not a recognized feature for this target (ignoring feature)
'++avx2' is not a recognized feature for this target (ignoring feature)
'++avx2' is not a recognized feature for this target (ignoring feature)

but if I remove the + I get:

error: custom attribute panicked
  --> src/main.rs:17:1
   |
17 | #[runtime_target_feature("avx2")]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: message: feature must begin with '+' or '-'

so it seems something along the line added an extra + breaking things.