hg: jdk/sandbox: Introduce EXTRA_SRC and supply headers as dirs.

[magnus.ihse.bursie at oracle.com]

Changeset: 2b67c11c0db6
Author:    ihse
Date:      2018-05-03 14:30 +0200
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/2b67c11c0db6

Introduce EXTRA_SRC and supply headers as dirs.

! make/common/JdkNativeCompilation.gmk
! make/lib/Awt2dLibraries.gmk
! make/lib/CoreLibraries.gmk
! make/lib/Lib-java.base.gmk
! make/lib/Lib-java.desktop.gmk
! make/lib/Lib-java.instrument.gmk
! make/lib/Lib-java.smartcardio.gmk
! make/lib/Lib-jdk.accessibility.gmk
! make/lib/Lib-jdk.jdi.gmk
! make/lib/Lib-jdk.jdwp.agent.gmk
! make/lib/Lib-jdk.pack.gmk
! make/lib/Lib-jdk.sctp.gmk
! make/lib/LibCommon.gmk