Unable to import multiple analysis in same TU

[HerbertJordan]

Due to the utilization of global management structures, including the

ProgramFactory *ProgramFactory::base __attribute__ ((weak)) = nullptr;

and

static factory_Sf_varpointsto_example factory;

it is not possible to import more than one analysis into a single C++ translation unit. We should try to get rid of those.

[b-scholz]

We needed these factories for finding any arbitrary analysis at runtime.
Could you preserve the functionality?

[HerbertJordan]

The call

ProgramFactory::find("my_analysis");

should still work -- and is also tested by the interface integration tests, as far as I know.

The Mechanism works as follows: The constructor of a factory is registering it within the list of factories maintained by the common base class ProgramFactory. This registering is triggered by the creation of a global factory variable of the proper type. I altered the code so that the global variable name contains now the name of the analysis, e.g. factory_points_to_analysis.

[b-scholz]

Great! We just need to be conscientious so that the Oracle Labs folk still can use a newer version of Souffle.