It's going to have to happen at some point... Reproducible: Always
rust useflag is already available. You just have to unmask the useflag which won't happen until firefox-54.x
'Rust' USE flag won't make much sense in the future because Rust is required for building Firefox 54[1][2]. It will make new Firefox unavailable to non-Tier-1[3] architectures which AFAIK aren't supported in Gentoo's Rust ebuild. [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1284816 [2] https://developer.mozilla.org/en-US/Firefox/Building_Firefox_with_Rust_code [3] https://forge.rust-lang.org/platform-support.html
So since Firefox 55 is already in tree, can be this one closed? "Support for building without Rust code was removed in bug 1284816. For Firefox 54 it's possible to build without Rust by patching out that and subsequent changes, but starting with Firefox 55 this becomes increasingly difficult and affects user security and available features." [1] [1] https://developer.mozilla.org/en-US/Firefox/Building_Firefox_with_Rust_code
Rust must made mandatory in 54.x we did not opt to patch it out, 55.0.1 is in tree and depends directly on virtual/rust
