Revert "nix-shell: Set $IN_NIX_SHELL before evaluation"
Revert "nix-shell: Set $IN_NIX_SHELL before evaluation"

This reverts commit 0c1198cf08576f16633b2344dc6513cefb567cfc.

dezgeg/nix,offlinehacker/nix,jcumming/nix,gridaphobe/nix,acowley/nix,ehmry/nix,gebner/nix,wmertens/nix,ehmry/nix,nbp/nix,vizanto/nix,bjornfor/nix,ysangkok/nix,ehmry/nix,dtzWill/nix,NixOS/nix,rycee/nix,pikajude/nix,ehmry/nix,vcunat/nix,offlinehacker/nix,rowhit/nix,edolstra/nix,peti/nix,vcunat/nix,bennofs/nix,ysangkok/nix,aucampia/nix,ttuegel/nix,wmertens/nix,NixOS/nix,layus/nix,acowley/nix,peti/nix,gridaphobe/nix,rycee/nix,aucampia/nix,dezgeg/nix,acowley/nix,garbas/nix,ttuegel/nix,vizanto/nix,ehmry/nix,tchajed/nix,bjornfor/nix,wmertens/nix,joelmo/nix,vizanto/nix,bennofs/nix,gridaphobe/nix,pikajude/nix,dezgeg/nix,offlinehacker/nix,dezgeg/nix,zimbatm/nix,dezgeg/nix,zimbatm/nix,tchajed/nix,shlevy/nix,layus/nix,dtzWill/nix,acowley/nix,edolstra/nix,edolstra/nix,jcumming/nix,vcunat/nix,rycee/nix,vizanto/nix,nbp/nix,layus/nix,gebner/nix,zimbatm/nix,peti/nix,dtzWill/nix,peti/nix,peti/nix,layus/nix,garbas/nix,tchajed/nix,dtzWill/nix,pikajude/nix,nbp/nix,joelmo/nix,ttuegel/nix,NixOS/nix,gebner/nix,rowhit/nix,nbp/nix,layus/nix,tchajed/nix,garbas/nix,NixOS/nix,rycee/nix,jcumming/nix,ehmry/nix,aucampia/nix,joelmo/nix,garbas/nix,vcunat/nix,garbas/nix,puffnfresh/nix,rowhit/nix,rowhit/nix,puffnfresh/nix,shlevy/nix,gridaphobe/nix,rycee/nix,bjornfor/nix,bjornfor/nix,ysangkok/nix,edolstra/nix,joelmo/nix,bennofs/nix,bennofs/nix,shlevy/nix,ttuegel/nix,NixOS/nix,gebner/nix,puffnfresh/nix,offlinehacker/nix,zimbatm/nix,dtzWill/nix,jcumming/nix,edolstra/nix,wmertens/nix,aucampia/nix,shlevy/nix,puffnfresh/nix,shlevy/nix