(Qinsufficient_source, Qinconsistent_eol)

(Qinsufficient_source, Qinconsistent_eol)
(Qinvalid_source, Qinterrupted, Qinsufficient_memory): New
variables.
(Vlast_code_conversion_error): New variables.
(syms_of_coding): DEFSYM or DEFVAR_LISP them.
(ONE_MORE_BYTE): Record error if any instead of signaling an
error.  If non-ASCII multibyte char is found, return the negative
value of the code.  All callers changed to check it.
(ONE_MORE_BYTE_NO_CHECK): Likewise.
(record_conversion_result): New function.  All codes setting
coding->result are changed to call this function.
(detect_coding_utf_8): Don't use the local variable incomplete.
(decode_coding_utf_8): Likewise.
(emacs_mule_char): Change the second arg to `const'.
(detect_coding_emacs_mule): Don't use the local variable
incomplete.
(detect_coding_sjis): Likewise.
(detect_coding_big5): Likewise.
(decode_coding): Fix of flushing out unprocessed data.
(make_conversion_work_buffer): Fix making of a work buffer.
(decode_coding_object): Return coding->dst_object;