diff --git a/collects/meta/drdr/plt-build.ss b/collects/meta/drdr/plt-build.ss
index d0791683f1..0ed865525c 100644
--- a/collects/meta/drdr/plt-build.ss
+++ b/collects/meta/drdr/plt-build.ss
@@ -282,6 +282,7 @@
                     [current-temporary-directory tmp-dir]
                     [current-rev rev])
        (with-env (["PLTSTDERR" "error"]
+                  ["GIT_DIR" (path->string (plt-repository))]
                   ["TMPDIR" (path->string tmp-dir)]
                   ["PATH" 
                    (format "~a:~a"