Bug 764590 is back when using the gold linker and GCC: 664:18.61 /usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: internal error in set_xindex, at /var/tmp/portage/sys-devel/binutils-2.37_p1/work/binutils-2.37/gold/object.h:1048 It looks like USE="lto -clang" used to imply mozconfig_add_options_ac "linker is set to bfd" --enable-linker=bfd but that line got lost somewhere.
Line is back in 91.4.0 and 95.0! Thank you for the report.