Repo for testing the QEMU segfault when building under emulation.

The relevant line in the flake is ERL_FLAGS = "+JPperf=true". Without this line a build with nix build .#packages.aarch64-linux.default fails when it runs under emulation on an x86 machine even when a non-emulated build with nix build .# succeeds. Uncommenting to add the flag causes the build to succeed in either case.