We rely on teaching go to use the correct ELF interpreter
for PIE in a way that can't work for packages that
go off and do their own GOARCH=something cross builds
without touching nixpkgs cross machinery,
so update the default pie patch to bake targetPlatform's
GOARCH and only activate for it.
tailscale works as a testcase for this as it cross compiles
many arches in tstest/archtest/qemu_test.go
dbb57d8d86