Relicense all public domain modules to CC0.
[ccan] / ccan / check_type /
drwxr-xr-x   ..
lrwxrwxrwx 18 LICENSE -> ../../licenses/CC0
-rw-r--r-- 841 _info
-rw-r--r-- 2373 check_type.h
drwxr-xr-x - test