* win32-nat.c (dll_symbol_command): Tack a .dll on the end of a supplied

* win32-nat.c (dll_symbol_command): Tack a .dll on the end of a supplied
argument if it is missing an extension.

* corelow.c: Define O_BINARY if it isn't defined.
(core_open): Open core file in binary mode.
* config/i386/tm-cygwin.h (child_clear_solibs): Rename from child_clear_solib.
* config/i386/cygwin.mh: Add dependency from corelow.o.
* win32-nat.c (register_loaded_dll): New function.  Add dll to the list of
currently loaded dlls.
(handle_load_dll): Use register_loaded_dll.
(child_solib_add): Distinguish between active process and core targets.
(solib_symbols_add): Load symbols from loaded dll.
(core_dll_symbols_add): New function.  Load symbols from dll referenced in
core.
(core_section_load_dll_symbols): New function.
(dll_code_sections_add): New function.
(map_single_dll_code_section): New function.
(fetch_elf_core_registers): New function.
(_initialize_core_win32): New function.