RFR: JDK-8147449: sjavac builds of jdk9/dev with closed sources broken

[Erik Joelsson]

Hello,

Please review this fix in the makefiles for using sjavac. The 
include/exclude mechanism in sjavac has changed. We used to sometimes 
exclude files using a full absolute path. This no longer works. The same 
thing can be achieved by splitting up the source roots argument to 
sjavac in separate -src arguments and then filter includes and excludes 
that are unique to a specific source root. Since this risks making 
command lines much longer, I also added a conditional 
ListPathsSafely/@file construct.

Bug: https://bugs.openjdk.java.net/browse/JDK-8147449
Webrev: http://cr.openjdk.java.net/~erikj/8147449/webrev.01/

/Erik