Simplify bignum->intmax conversion

Simplify bignum->intmax conversion

* src/lisp.h (integer_to_intmax, integer_to_uintmax): New functions.
* src/data.c (cons_to_unsigned, cons_to_signed)
(arith_driver):
* src/dbusbind.c (xd_extract_signed, xd_extract_unsigned):
* src/dispnew.c (sit_for):
* src/editfns.c (styled_format):
* src/emacs-module.c (module_extract_integer):
* src/fileio.c (file_offset):
* src/font.c (font_unparse_xlfd, Fopen_font):
* src/xdisp.c (calc_line_height_property):
* src/process.c (handle_child_signal):