pub const InstallDir = union(enum) {
    prefix: void,
    lib: void,
    bin: void,
    header: void,
    /// A path relative to the prefix
    custom: []const u8,

    /// Duplicates the install directory including the path if set to custom.
    pub fn dupe(dir: InstallDir, builder: *Build) InstallDir {
        if (dir == .custom) {
            return .{ .custom = builder.dupe(dir.custom) };
        } else {
            return dir;
        }
    }
}