pkgs/posh: spawn login shell

When bash is spawned as a login shell it automatically loads some of the
default profile paths, including `/etc/profile` and `$HOME/.profile`.

nix/pkgs/posh.nix

@@ -167,7 +167,7 @@ in
   source /etc/profile
 
   test -S "$SSH_AUTH_SOCK" && ssh="-v $SSH_AUTH_SOCK:$SSH_AUTH_SOCK -e SSH_AUTH_SOCK"
-  tty -s && tty="-t" || quiet="-q"
+  tty -s && tty="-t" entrypoint=--entrypoint='["/usr/bin/env","bash","-il"]' || quiet="-q"
 
   # define these as variables so we can override them at runtime
   POSH_IMAGE=${image}
@@ -179,6 +179,8 @@ in
     # TODO parse the beginning of the command for POSH_* overrides
   fi
 
+  test "$@" && cmd=( -c "$@")
+
   HOME_CONTAINERS_CONFIGDIR="$HOME/.config/containers"
   HOME_POLICY_JSON="$HOME_CONTAINERS_CONFIGDIR/policy.json"
   test -d $HOME_CONTAINERS_CONFIGIDR || mkdir $HOME_CONTAINERS_CONFIGIDR
@@ -188,7 +190,8 @@ in
     ${global_args} run --rm -i $tty $ssh -v ~/:/root -w /root --network host --pull=''${POSH_PULL} \
     --conmon ${pkgs.conmon}/bin/conmon --runtime ${pkgs.runc}/bin/runc \
     --config ${podmanConfig} \
-    ${run_args} ''${POSH_IMAGE} $@
+    ${run_args} \
+    ''${POSH_IMAGE} /usr/bin/env bash -l "''${cmd[@]}"
 '')
 .overrideAttrs(attrs: attrs // {
     passthru = {