git subrepo clone --branch=0.30.3 https://github.com/commonmark/cmark.git deps/cmark

subrepo:
  subdir:   "deps/cmark"
  merged:   "5ba25ff"
upstream:
  origin:   "https://github.com/commonmark/cmark.git"
  branch:   "0.30.3"
  commit:   "5ba25ff"
git-subrepo:
  version:  "0.4.6"
  commit:   "d4444b563"

deps/cmark/test/afl_test_cases/test.md

@@ -0,0 +1,36 @@
+# H1
+
+H2
+--
+
+t ☺  
+*b* **em** `c`
+≥\&\
+\_e\_
+
+4) I1
+
+5) I2
+   > [l](/u "t")
+   >
+   > - [f]
+   > - ![a](/u "t")
+   >
+   >> <ftp://hh>
+   >> <u@hh>
+
+~~~ l☺
+cb
+~~~
+
+    c1
+    c2
+
+***
+
+<div>
+<b>x</b>
+</div>
+
+[f]: /u "t"
+