Relicense all public domain modules to CC0.

[ccan] / ccan / container_of / LICENSE

diff --git a/ccan/container_of/LICENSE b/ccan/container_of/LICENSE
new file mode 120000 (symlink)
index 0000000..b7951da
--- /dev/null
+++ b/ccan/container_of/LICENSE
@@ -0,0 +1 @@
+../../licenses/CC0
\ No newline at end of file