Explicitly pass -std=gnu++03 to the compiler.
This fixes the build with GCC 6, which defaults to -std=gnu++14. The port's
code does not work with C++11 or later.
Fixing it also requires adjusting Makefile.in so that invoking the C++ compiler
uses CXXFLAGS, not CFLAGS.
Add annoyance-filter 1.0b, Adaptive Bayesian Junk Mail Filter.
annoyance-filter uses Bayesian statistics to determine the probability
an E-mail message is junk based on an analysis of its contents compared
to collections of known junk and legitimate E-mail.
Suggested by: phk