JDK14p4 plugin build fails

[Andrew Houghton]

For what it's worth, copying the entire header directory contents 
(/usr/X11R6/include/mozilla/nspr) into the mozilla_headers_ns600 and 
mozilla_headers_ns610 directories allows the build to complete.  The 
plugin itself doesn't appear to work, but I haven't done a lot of 
testing here yet.

I'm sure there's a more elegant solution, but setting 
ALT_MOZILLA_HEADERS_PATH in the Makefile didn't seem to help.

Any ideas why this might have occurred?

- a.