* Introduce GCBI::buildDispatcher
* Introduce GCBI::getJumpTarget{,Block} and GCBI::getBlocksGeneratedByPC
to easily map `BasicBlock *` to jump targets and viceversa.
* PCH::buildDispatcher now returns a list of the newly created basic
blocks.
* Other minor changes
This commit fixes a bug that lead to be unable to instantiate from a
`Module` `ProgramCounterHandler`. The reason for this was that
`ProgramCounterHandler` was using `Module::getGlobalVariable` which, by
default, ignores variables with internal linkage.
Alessandro Di Federico