diff --git a/Modules/Setup b/Modules/Setup
index e2b5f86..e7b939d 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -180,6 +180,7 @@
 #_bisect _bisectmodule.c	# Bisection algorithms
 #_heapq _heapqmodule.c	# Heap queue algorithm
 #_asyncio _asynciomodule.c  # Fast asyncio Future
+#_json -I$(srcdir)/Include/internal -DPy_BUILD_CORE_BUILTIN _json.c	# _json speedups
 
 #unicodedata unicodedata.c    # static Unicode character database