diff --git a/tests/build/build-opts.txt b/tests/build/build-opts.txt
index d7953d89..a22b3c57 100644
--- a/tests/build/build-opts.txt
+++ b/tests/build/build-opts.txt
@@ -30,4 +30,5 @@ CPPFLAGS=-DSEXP_USE_PROFILE_VM=1
 CPPFLAGS=-DSEXP_USE_UTF8_STRINGS=0
 CPPFLAGS=-DSEXP_USE_STATIC_LIBS=1
 CPPFLAGS=-DSEXP_USE_MUTABLE_STRINGS=0
+CPPFLAGS=-DSEXP_USE_STRICT_TOPLEVEL_BINDINGS=1
 CPPFLAGS=-DSEXP_USE_NO_FEATURES=1