Review request for 7034570

[Michael McMahon]

This issue occurs on some versions of Windows since we switched compiler
to VC 2010. The new C runtime library requires the "SystemRoot" environment
variable to be set, when launching sub-processes via Runtime.exec() or 
ProcessBuilder.

The problem occurs in instances where the environment is specified by 
the caller,
rather than simply inheriting (or inheriting and adding to) the 
environment of the parent
process.

The change is simple enough. We just check for the presence of 
"SystemRoot" in the
child process's environment, and set it if it's not there.  No change 
will be visible
to the parent process. But, to avoid ambiguity, we'd like to make the 
change explicit
with a small spec. change.

http://cr.openjdk.java.net/~michaelm/7034570/webrev.1/

Thanks,
Michael.