AC_CHECK_RQRD_CLASS tests the existence of a given Java class, either in
a jar or in a '.class' file and fails if it doesn't exist.
Its success or failure can depend on a proper setting of the
CLASSPATH env. variable.
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
The general documentation, as well as the sample configure.in, is
included in the AC_PROG_JAVA macro.