www/firefox: Unbreak build with Rust 1.56.0
error[E0557]: feature has been removed
--> /wrkdirs/usr/ports/www/firefox/work/firefox-93.0/third_party/rust/packed_simd/src/lib.rs:203:5 |
203 | const_generics,
| ^^^^^^^^^^^^^^ feature has been removed | = note: removed in favor of `#![feature(adt_const_params]` and `#![feature(generic_const_exprs)]`
PR: 259251