This module first checks whether the inc/.author directory exists,
and removes the whole inc/ directory if it does, so the module author
always get a fresh inc every time they run Makefile.PL. Next, it
unshifts inc into @INC, then loads <B>Module::InstallB> from there.
Below is an explanation of the reason for using a loader module:
The original implementation of <B>CPAN::MakeMakerB> introduces subtle
problems for distributions ending with CPAN (e.g. <B>CPAN.pmB>,
<B>WAIT::Format::CPANB>), because its placement in ./CPAN/ duplicates
the real libraries that will get installed; also, the directory name
./CPAN/ may confuse users.
On the other hand, putting included, for-build-time-only libraries in
./inc/ is a normal practice, and there is little chance that a
CPAN distribution will be called Something::inc, so its much safer
Also, it allows for other helper modules like <B>Module::AutoInstallB>
to reside also in inc/, and to make use of them.