Poor performance in DirectoryArchiver due to unnecessary native calls

1)
maven-assembly-plugin calls DirectoryArchiver.copyFile( ArchiveEntry entry, String vPath ), which calls
ArchiveEntryUtils.chmod( outFile, entry.getMode(), getLogger() );
resulting in a native child Process being forked to do a chmod (on Unix only)

The performance impact on a large assembly is enormous: patching DirectoryArchiver to not do this resulted in a performance improvement by more than 5 times.
I've raised this with Plexus as http://jira.codehaus.org/browse/PLXCOMP-156

2)
AssemblyFormatUtils should cache the environment, as AssemblyInterpolator does. Both, though, should use the latest plexus CommandLineUtils, as opposed to maven-assembly-plugin's own version. The plexus class uses System.getenv() (JDK5+) when available.

Generally, please see if you can review the use of native command calls, esp. in light of JDK5/6 APIs. Forked native calls had a horrible performance impact on our (large, highly modular) assembly; which has only been corrected by local patches of maven-assembly/plexus-archiver.
Thanks!