[Bug #19016] Handle syntax error in main script like other errors

So that `SyntaxError#detailed_message` will be used also in the case
exiting by such syntax error.

eval.c

@@ -121,6 +121,7 @@ ruby_options(int argc, char **argv)
     else {
         rb_ec_clear_current_thread_trace_func(ec);
         state = error_handle(ec, state);
+        ec->errinfo = Qnil; /* just been handled */
         iseq = (void *)INT2FIX(state);
     }
     EC_POP_TAG();
@@ -317,7 +318,7 @@ ruby_run_node(void *n)
     rb_execution_context_t *ec = GET_EC();
     int status;
     if (!ruby_executable_node(n, &status)) {
-        rb_ec_cleanup(ec, 0);
+        rb_ec_cleanup(ec, (NIL_P(ec->errinfo) ? TAG_NONE : TAG_RAISE));
         return status;
     }
     ruby_init_stack((void *)&status);

test/ruby/test_exception.rb

@@ -1457,4 +1457,21 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
     assert_match("BOO!", e.full_message.lines.first)
     assert_equal({ highlight: Exception.to_tty? }, opt_)
   end
+
+  def test_syntax_error_detailed_message
+    Tempfile.create(%w[detail .rb]) do |lib|
+      lib.print "#{<<~"begin;"}\n#{<<~'end;'}"
+      begin;
+        class SyntaxError
+          def detailed_message(**)
+            Thread.start {}.join
+            "#{super}\n""<#{File.basename(__FILE__)}>"
+          end
+        end
+      end;
+      lib.close
+      pattern = /^<#{Regexp.quote(File.basename(lib.path))}>/
+      assert_in_out_err(%W[-r#{lib.path} -], "1+", [], pattern)
+    end
+  end
 end