8182299: Enable disabled clang warnings, build on OSX 10 + Xcode 8
8182656: Make the required changes in GC code to build on OSX 10 + Xcode 8
8182657: Make the required changes in Runtime code to build on OSX 10 + Xcode 8
8182658: Make the required changes in Compiler code to build on OSX 10 + Xcode 8
Reviewed-by: jwilhelm, ehelin

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