Created attachment 677206 [details] emerge --info upstream bug with patch: https://bugzilla.mozilla.org/show_bug.cgi?id=1677690
Created attachment 677209 [details] build.log
Thank you for letting us know. But we will not backport because Firefox 84 is around the corner and will contain the fix.
I mean the fix ( https://hg.mozilla.org/mozilla-central/rev/ebe83e59605b ) applied and worked just fine for 83 for me, but waiting a week for 84 shouldn't be too big of a deal for others I guess.
I think this is fixed, just compiled firefox-87.0 the other day with gcc
Yeah 84 did fix it.