message: make Mat_AUTO_STEP constant usize
diff: @@ -1301,6 +1301,7 @@ class ConstInfo(GeneralInfo):
  TEMPLATES = {
  "rust_string": template("${doccomment}pub const ${name}: &'static str = ${value};\n"),
  "rust_int": template("${doccomment}pub const ${name}: i32 = ${value};\n"),
  + "rust_usize": template("${doccomment}pub const ${name}: usize = ${value};\n"),
  "cpp_string": template(""" printf("pub static ${name}: &'static str = \\"%s\\";\\n", ${full_name});\n"""),
  "cpp_double": template(""" printf("pub const ${name}: f64 = %f;\\n", ${full_name});\n"""),
  "cpp_int": template(""" printf("pub const ${name}: i32 = 0x%x; // %i\\n", ${full_name}, ${full_name});\n"""),
  @@ -1338,6 +1339,8 @@ class ConstInfo(GeneralInfo):
  doccomment = "/// {}\n".format(m.group(3) if m.group(2) is None else m.group(2))
  if value.startswith('"'):
  return ConstInfo.TEMPLATES["rust_string"].substitute(doccomment=doccomment, name=name, value=value)
  + elif name in ("Mat_AUTO_STEP", ""):
  + return ConstInfo.TEMPLATES["rust_usize"].substitute(doccomment=doccomment, name=name, value=value)
  elif re.match(r"^(-?[0-9]+|0x[0-9A-Fa-f]+)$", value): # decimal or hexadecimal
  return ConstInfo.TEMPLATES["rust_int"].substitute(doccomment=doccomment, name=name, value=value)
  elif re.match(r"^\(?\s*(\d+\s*<<\s*\d+)\s*\)?$", value): # (1 << 24)
  