* win32-nat.c (safe_symbol_file_add_stub): Improve logic for avoiding load of

* win32-nat.c (safe_symbol_file_add_stub): Improve logic for avoiding load of
already loaded DLL.
(register_loaded_dll): Convert loaded DLL name to "posix" format or it will
confuse subsequent opening of the filename due to dos paths.
(dll_symbol_command): Pass from_tty parameter to safe_symbol_file_add.