8081315: 8077982 giflib upgrade breaks system giflib builds with earlier versions
Summary: Add conditionals to provide giflib < 5 API calls and interlacing behaviour
Reviewed-by: prr, azvegint

8077982: GIFLIB upgrade
Reviewed-by: ant, serb

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