>> Now something I don't understand is how reportlab distribution is doing
>> to copy the compiled extensions when "install" is called.
> I think clib stuff is installed in the right python directory and the
> ext install step then just finds them.
Yep, the install* commands just copy all files from the build dir to the install dir.

The patch is straightforward and the test looks good.  However, I worry about backward compatibility.  For projects without C libs, this won’t change anything; for projects already having a workaround, what will happen?  While this is clearly a bug, I’m not sure fixing the existing behavior is okay in distutils.

For packaging (distutils2), I will commit this shortly.