Most FHSEnv-wrapped packages in Nixpkgs wrap a x86_64-linux binary; making
multiArch unnecessary bloat closure size. Saves about 1G in anki-bin.
This makes multiArch FHSEnvs the exception rather than the rule.
This reverts commit 840f2e0ac5, reversing
changes made to d3ed0402e5.
This breaks appimage which puts args into the runScript and we don't provide a
good way to pass thru additional args.
The actual bug was in nix-alien which should escape paths; providing a valid
runScript is the responsibility of the caller.
