JDK Makefiles (specifically, j2se/make/common/Defs.gmk)
should define JDK_UPDATE_VERSION for update versions,
instead of requiring users to pass it in on the command line
or via an environment variable.

Else it is too easy to build a java that claims to be the wrong version.
It is too hard to identify the version of a teamware workspace.

All the very good reasons to put JDK_(MAJOR|MINOR|MICRO)_VERSION into the
Makefiles apply equally well to JDK_UPDATE_VERSION (for update releases
only, of course)

###@###.### 2004-09-15