Auto merge of #2295 - Wind-River:master, r=JohnTitor
Auto merge of #2295 - Wind-River:master, r=JohnTitor

Add error codes and one function for VxWorks

These error codes exist for VxWorks, but were not required for rustc
previously. The same happened for sigaddset.

rust-lang/libc,rust-lang/libc,rust-lang/libc