Fix deprecated NetBSD sigaction/sigaltstack symbols
Fix deprecated NetBSD sigaction/sigaltstack symbols

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