If the SpamAssassin module fails to build, there are three probable reasons:
In these conditions, CPAN will not install the module.
If a dependency is missing, it will be reported during the initial
perl Makefile.PL as a warning. If this dependency is not resolved, then when
make test is run, some tests for the module will probably fail. Additionally, the module may fail to operate properly if installed. The solution is to install the dependency and repeat the testing process. If SpamAssassin fails to build, this will probably be due to the non-compilation of the parts of SpamAssassin ...