diff --git a/build/pkgs/sagelib/spkg-install.in b/build/pkgs/sagelib/spkg-install.in
index ff883b5fcb2..5c78e3459c8 100644
--- a/build/pkgs/sagelib/spkg-install.in
+++ b/build/pkgs/sagelib/spkg-install.in
@@ -24,11 +24,10 @@ export SAGE_ROOT=/doesnotexist
 export SAGE_SRC=/doesnotexist
 export SAGE_SRC_ROOT=/doesnotexist
 export SAGE_DOC_SRC=/doesnotexist
-export SAGE_BUILD_DIR=/doesnotexist
 
-# We also poison all directories below SAGE_LOCAL.
+# We also poison all directories below SAGE_LOCAL
+# except for SAGE_SPKG_SCRIPTS, which is needed by sage-dist-helpers
 export SAGE_PKGCONFIG=/doesnotexist
-export SAGE_SPKG_SCRIPTS=/doesnotexist
 export SAGE_SHARE=/doesnotexist
 
 # However, we only unset SAGE_LOCAL and SAGE_PKG_CONFIG_PATH.