* autoload.cc (LoadFuncEx): Define via new LoadFuncEx2 macro.

* autoload.cc (LoadFuncEx): Define via new LoadFuncEx2 macro.
(LoadFuncEx2): Adapted from LoadFuncEx.  Provides control of return value for
nonexistent function.
(NtQueryObject): Declare.
(IsDebuggerPresent): Declare via LoadFuncEx2 and always return true if not
available.
* debug.h (being_debugged): Just rely on IsDebuggerPresent return value.
* dtable.cc (handle_to_fn): New function.
(dtable::init_std_file_from_handle): Attempt to derive std handle's name via
handle_to_fn.
(dtable::build_fhandler_from_name): Fill in what we can in path_conv structure
when given a handle and path doesn't exist.
* fhandler.cc (fhandler_base::open): Don't set the file pointer here.  Use
pc->exists () to determine if file exists rather than calling GetFileAttributes
again.
* fhandler.h (fhandler_base::exec_state_isknown): New method.
(fhandler_base::fstat_helper): Add extra arguments to declaration.
(fhandler_base::fstat_by_handle): Declare new method.
(fhandler_base::fstat_by_name): Declare new method.
* fhandler_disk_file (num_entries): Make __stdcall.
(fhandler_base::fstat_by_handle): Define new method.
(fhandler_base::fstat_by_name): Define new method.
(fhandler_base:fstat): Call fstat_by_{handle,name} as appropriate.
(fhandler_disk_file::fstat_helper): Accept extra arguments for filling out stat
structure.  Move handle or name specific stuff to new methods above.
(fhandler_disk_file::open): Use real_path->exists rather than calling
GetFileAttributes again.
* ntdll.h (FILE_NAME_INFORMATION): Define new structure.
(OBJECT_INFORMATION_CLASS): Partially define new enum.
(OBJECT_NAME_INFORMATION): Define new structure.
(NtQueryInformationFile): New declaration.
(NtQueryObject): New declaration.
* path.cc (path_conv::fillin): Define new method.
* path.h (path_conv::fillin): Declare new method.
(path_conv::drive_thpe): Rename from 'get_drive_type'.
(path_conv::volser): Declare new method.
(path_conv::volname): Declare new method.
(path_conv::root_dir): Declare new method.
* syscalls.cc (fstat64): Send real path_conv to fstat as second argument.