8154454: Fix compilation issue in PlainSocketImpl
Reviewed-by: chegar

8154238: Drop code to support Windows XP in windows socket impl
Reviewed-by: chegar

6432031: Add support for SO_REUSEPORT
Reviewed-by: alanb, simonis, chegar
Contributed-by: yingqi.lu@intel.com

8054834: Modular Source Code
Reviewed-by: alanb, chegar, ihse, mduigou
Contributed-by: alan.bateman@oracle.com, alex.buckley@oracle.com, chris.hegarty@oracle.com, erik.joelsson@oracle.com, jonathan.gibbons@oracle.com, karen.kinnear@oracle.com, magnus.ihse.bursie@oracle.com, mandy.chung@oracle.com, mark.reinhold@oracle.com, paul.sandoz@oracle.com