diff --git a/ext/json/parser/prereq.mk b/ext/json/parser/prereq.mk
new file mode 100644
index 0000000000..be7bcb4319
--- /dev/null
+++ b/ext/json/parser/prereq.mk
@@ -0,0 +1,10 @@
+RAGEL = ragel
+
+.SUFFIXES: .rl
+
+.rl.c:
+	$(RAGEL) -G2 $<
+	$(BASERUBY) -pli -e '$$_.sub!(/[ \t]+$$/, "")' \
+	-e '$$_.sub!(/^static const int (JSON_.*=.*);$$/, "enum {\\1};")' $@
+
+parser.c: