* dll_init.cc (dll_list::alloc): Compare linked DLLs by basename only.
Explain why. Add code to check if a DLL with the same basename but
different path is the same DLL. Bail out if not.
(in_load_after_fork): New static NO_COPY bool to allow to differ
between linked and loaded DLL at fork.
(dll_list::load_after_fork): Set in_load_after_fork accordingly.
(dll_dllcrt0_1): Don't treat DLL as linked if in_load_after_fork is set.
Drop test for in_forkee.