The attached patch lets devel/libowfat build with clang on CURRENT.
Without the patch the build fails with:
In file included from t.c:27:
./CAS.h:56:3: error: void function 'atomic_add' should not return a value [-Wreturn-type]
The patch has been sent to the upstream as well.
Fix: Patch attached with submission follows:
Over to maintainer (via the GNATS Auto Assign Tool)
Fixed in r311827. Thanks!