Comment 89 for bug 1921664

The impact of this bug is reported as being that emulation of riscv64 on arm64 hardware fails. But the change that's been introduced affects the build flags for all binaries, not just qemu-system-riscv64; and affects the build flags for all non-amd64 *architectures*, not just arm64. Since LTO is an optimization, please provide further justification for the widespread reversion of this build flag instead of a targeted fix, or provide evidence that it does not significantly reduce performance.