gcov-io.h (gcov_save_position, [...]): Modified to enable reading/ writing of whole .da file just once.

	* gcov-io.h (gcov_save_position, gcov_reserve_length, gcov_resync,
	gcov_skip, gcov_skip_string, gcov_write_unsigned, gcov_write_counter,
	gcov_write_string, gcov_read_unsigned, gcov_read_counter,
	gcov_read_string, gcov_write_length): Modified to enable reading/
	writing of whole .da file just once.
	(da_file_open, da_file_close, da_file_eof, da_file_error,
	da_file_position, da_file_seek, da_file_write, da_file_read): New
	functions.
	(actual_da_file, actual_da_file_position, actual_da_file_length,
	actual_da_file_buffer, actual_da_file_buffer_size): New static
	functions.
	* libgcov.c (gcov_exit): Modified to read/write the whole .da file at
	just once.

From-SVN: r63800