Fix warnings_once.t to not die if Test::NoWarnings isn't installed.
-rw-r--r-- .gitignore
-rw-r--r-- .shipit
-rw-r--r-- Changes
-rw-r--r-- MANIFEST.SKIP
-rw-r--r-- dist.ini
drwxr-xr-x lib
drwxr-xr-x t
drwxr-xr-x xt