Revert "Remove some bashisms from configure.ac"
Revert "Remove some bashisms from configure.ac"

This reverts commit e8b0efdcc9d6329b299937790360cac8b9b256c9.

zimbatm/nix,zimbatm/nix,ehmry/nix,rycee/nix,NixOS/nix,rycee/nix,NixOS/nix,pikajude/nix,dtzWill/nix,vcunat/nix,dtzWill/nix,ehmry/nix,vcunat/nix,zimbatm/nix,ehmry/nix,pikajude/nix,dtzWill/nix,NixOS/nix,ehmry/nix,rycee/nix,pikajude/nix,NixOS/nix,rycee/nix,vcunat/nix,vcunat/nix,dtzWill/nix,dtzWill/nix,NixOS/nix,ehmry/nix,rycee/nix,zimbatm/nix,ehmry/nix