Streams: Further considerations

Streams' gets function does not work with stdio, because it uses fread(3) instead of fgets(3). Like fill_read_buffer earlier, fread(3) does not return, unless an error occurs or the amount of data has been read completely. It is basically impossible to implement an _efficient_ fgets-like function using fread(3). Additionally, stdio does its own buffering -- there is no reason to add another buffer layer above it. The streams buffer needs to be disabled, because fgets/fread would otherwise interact wrongly. The attached patch does this: - Disables buffering for stdio using PHP_STREAM_FLAG_NO_BUFFER - Adds a gets hook to stream ops - Adds a gets implementation to stdio ops - Makes stream_gets use that hook, if available - Inverts the semantic of fill_read_buffer regarding blocking "make test" and entering data using stdin works. Comments, please. - Sascha