diff --git a/build.go b/build.go
index d8fe9d3..e7eb48f 100644
--- a/build.go
+++ b/build.go
@@ -505,8 +505,8 @@ func getSources(ctx context.Context, srcdir string, bv *BuildVars) error {
 
 // setDirVars sets srcdir and pkgdir. It's a very hacky way of doing so,
 // but setting the runner's Env and Vars fields doesn't seem to work.
-func setDirVars(ctx context.Context, runner *interp.Runner, srcdir, pkgdir string) error {
-	cmd := "srcdir='" + srcdir + "'\npkgdir='" + pkgdir + "'\n"
+func setDirVars(ctx context.Context, runner *interp.Runner, srcdir, pkgdir, repodir string) error {
+	cmd := "srcdir='" + srcdir + "'\npkgdir='" + pkgdir + "'\nrepodir='" + repodir + "'\n"
 	fl, err := syntax.NewParser().Parse(strings.NewReader(cmd), "vars")
 	if err != nil {
 		return err