Modern autoconf deprecated macros, some configure.ac logic errors.

[sshambar]

Autoconf complains that some macros are obsolete. Also, automake complains of rules for .class and .jar files being redefined. Also cached tests are used if I2util is a sub-directory (so builds break if I2util is not installed). A reference to JAnalyze_JAVA is incorrect.

I'll submit a pull request with fixes for the above, and also remove the unused/outdated config/c-attribute.m4 macro, and add support for autoreconf to work correctly.

Thanks,
Scott