Print import errors when DEBUG is set

c/jsc-test.c

		JSStringRef script_ref = JSStringCreateWithUTF8CString(buf);
		free(buf);
		JSEvaluateScript(ctx, script_ref, NULL, path_str_ref, 0, NULL);
		JSValueRef ex = NULL;
		JSEvaluateScript(ctx, script_ref, NULL, path_str_ref, 0, &ex);
		JSStringRelease(script_ref);
#ifdef DEBUG
		if (ex != NULL) {
			JSStringRef ex_str = to_string(ctx, ex);
			char ex_buf[1000];
			ex_buf[0] = '\0';
			JSStringGetUTF8CString(ex_str, ex_buf, 1000);
			printf("import: %s\n", ex_buf);
			JSStringRelease(ex_str);
		}
#endif
	}
	return JSValueMakeUndefined(ctx);