RFR: JDK-8211016: make images does not update jdk/lib/src.zip with latest changes

[Erik Joelsson]

The incremental build of src.zip is broken. The cause of this is a bit 
complex. To create the correct layout for the files in src.zip, we 
create a set of directories with symlinks back to the real source. When 
we then run find over these symlinked directories to figure out the make 
dependencies, find will not follow symlinks by default.

The fix adds -L to find only when creating zip files. I think this is 
the right thing to do because zip will follow symlinks by default as 
well, so it keeps the behavior of the makefile and the resulting zip 
file the same. I don't think we should always follow symlinks when 
finding files however, because most of the time, we do want the links 
rather than their targets in the result.

While investigating I also decided to wrap the zip commands in 
ExecuteWithLog. Note that since zip is called in a loop, only the output 
of the last call will end up in the log. I think this is ok because 
successful runs should not produce output, and make will terminate on 
failure anyway.

Bug: https://bugs.openjdk.java.net/browse/JDK-8211016

Webrev: http://cr.openjdk.java.net/~erikj/8211016/webrev.01/index.html

/Erik