Merge two string slices, only adding values from set2 that were not already present in set1.

Check if the string in the check variable is a member of the set of strings.

Given a slice of strings, return the slice without the string in the rm variable, if it exists in the set.

All values for runtime.GOOS, derived from https://github.com/golang/go/blob/master/src/go/build/syslist.go .

A values for runtime.GOOS that are unix-like .