cmd/nix-tool: pass --store via extraArgs

Sleepy me forgot about passing extraArgs :c

cmd/nix-tool/chroot.go

@@ -1,17 +0,0 @@
-package main
-
-import (
-	"context"
-	"os/exec"
-
-	"gensokyo.uk/nix"
-)
-
-type chrootStoreContext struct {
-	store string
-	nix.Context
-}
-
-func (c *chrootStoreContext) Nix(ctx context.Context, arg ...string) *exec.Cmd {
-	return c.Context.Nix(ctx, append([]string{"--store", c.store}, arg...)...)
-}

cmd/nix-tool/main.go

@@ -36,16 +36,17 @@ func main() {
 	c := command.New(os.Stderr, log.Printf, "nix-tool", func(args []string) error {
 		log.SetFlags(0)
 
+		var extraArgs []string
+		flagStore = strings.TrimSpace(flagStore)
+		if flagStore != string(os.PathSeparator) {
+			extraArgs = append(extraArgs, "--store", flagStore)
+		}
+
 		var stderr io.Writer
 		if flagVerbose {
 			stderr = os.Stderr
 		}
-		ctx = nix.New(nixCtx, nil, os.Stdout, stderr)
+		ctx = nix.New(nixCtx, extraArgs, os.Stdout, stderr)
-
-		flagStore = strings.TrimSpace(flagStore)
-		if flagStore != string(os.PathSeparator) {
-			ctx = &chrootStoreContext{flagStore, ctx}
-		}
 
 		return nil
 	}).