8167424: Various trivial fixes in build system
Reviewed-by: erikj, tbell

8003593: build-infra: Paths to optional platform-specific files should not be hardwired to src/closed
Reviewed-by: dholmes, prr

8146403: Windows build can be faster
Reviewed-by: ihse

Merge

8058631: Rename posix to unix in build system to match file name changes
Reviewed-by: simonis, erikj, tbell

8049367: Modular Run-Time Images
Reviewed-by: chegar, dfuchs, ihse, joehw, mullan, psandoz, wetmore
Contributed-by: alan.bateman@oracle.com, alex.buckley@oracle.com, bradford.wetmore@oracle.com, chris.hegarty@oracle.com, erik.joelsson@oracle.com, james.laskey@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, sundararajan.athijegannathan@oracle.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

8034173: Move JavaApp.icns to proper place in make/data
Reviewed-by: ihse, tbell

8027566: Remove the old build system
Reviewed-by: erikj, tbell