* coding.c (coding_set_destination): Use BEG_BYTE rather than hardcoding 1.

* coding.c (coding_set_destination): Use BEG_BYTE rather than hardcoding 1.
(detect_coding_system):
* lisp.h (detect_coding_system, chars_in_text, multibyte_chars_in_text)
(string_char_to_byte, string_byte_to_char, insert_from_gap):
* insdel.c (insert_from_gap):
* fns.c (string_char_byte_cache_charpos, string_char_byte_cache_bytepos)
(string_char_to_byte, string_byte_to_char, string_make_multibyte)
(string_to_multibyte):
* character.c (chars_in_text, multibyte_chars_in_text):
* fileio.c (Finsert_file_contents): Use EMACS_INT for buffer positions.