I propose to backport four langtools bug fixes from JDK 7 to OpenJDK 6

[Jim Holmlund]

The webrevs are

http://cr.openjdk.java.net/~jjh/6502392-openJDK6/
http://cr.openjdk.java.net/~jjh/7003006-openJDK6/
http://cr.openjdk.java.net/~jjh/6999460-openJDK6/
http://cr.openjdk.java.net/~jjh/6999891-openJDK6/

The fix for 6999420 has already been approved- this is the bug about building Glassfish being very 
slow on Windows.

The other three fixes are basically to the same file, JavacFileManager.java, and were 'easy' to 
backport.
I request that you approve them.

Thanks.
- jjh