Further linux build refinements

Author: michael-lehew

Foundation/Data.swift

@@ -270,7 +270,7 @@ public struct Data : ReferenceConvertible, CustomStringConvertible, Equatable, H
     ///
     /// - parameter reference: The instance of `NSData` that you wish to wrap. This instance will be copied by `struct Data`.
     public init(referencing reference: NSData) {
-        _wrapped = _SwiftNSData(immutableObject: reference.copy() as AnyObject)
+        _wrapped = _SwiftNSData(immutableObject: reference.copy() as! AnyObject)
     }
 
     // -----------------------------------

Foundation/NSData.swift

@@ -233,7 +233,7 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
             return false
         }
 
-        return other.withUnsafeBytes { (bytes2: UnsafePointer<Void>) -> Bool in
+        return other.withUnsafeBytes { (bytes2: UnsafePointer<UInt8>) -> Bool in
             let bytes1 = bytes
             return memcmp(bytes1, bytes2, length) == 0
         }