AC_CHECK_CLASSPATH just displays the CLASSPATH, for the edification
of the user.
Note: This is part of the set of autoconf M4 macros for Java programs.
It is VERY IMPORTANT that you download the whole set, some
macros depend on other. Unfortunately, the autoconf archive does not
support the concept of set of macros, so I had to break it for
submission.
The general documentation, as well as the sample configure.in, is
included in the AC_PROG_JAVA macro.