libc-test: ignore user-defined struct
libc-test: ignore user-defined struct

rust-lang-nursery/libc,anatol/libc,cactorium/libc,rust-lang/libc,mneumann/libc,anatol/libc,zethra/libc,philippkeller/libc,anatol/libc,zethra/libc,rust-lang/libc,rust-lang-nursery/libc,superriva/libc,superriva/libc,cactorium/libc,mneumann/libc,philippkeller/libc,rust-lang-nursery/libc,philippkeller/libc,rust-lang/libc,zethra/libc,superriva/libc,cactorium/libc,mneumann/libc