For relative paths in INPUT() and GROUP(), search the directory of the current linker...

For relative paths in INPUT() and GROUP(), search the directory of the current linker script before searching other paths.

	PR ld/25806
	* ldlang.h (struct lang_input_statement_struct): Add extra_search_path.
	* ldlang.c (current_input_file): New.
	(ldirname): New.
	(new_afile): Add from_filename parameter. Set extra_search_path.
	(lang_add_input_file): Pass current_input_file to new_afile.
	(load_symbols): Set current_input_file.