# File lib/mkmf.rb, line 773
def have_type(type, headers = nil, opt = "", &b)
  checking_for checking_message(type, headers, opt) do
    headers = cpp_include(headers)
    if try_compile("\#{COMMON_HEADERS}\n\#{headers}\n/*top*/\ntypedef \#{type} conftest_type;\nstatic conftest_type conftestval[sizeof(conftest_type)?1:-1];\n", opt, &b)
      $defs.push(format("-DHAVE_TYPE_%s", type.strip.upcase.tr_s("^A-Z0-9_", "_")))
      true
    else
      false
    end
  end
end