Bug: Cosmopolitan Python's `sys.platform` always returns 'linux'

### Contact Details yjf_victor@hotmail.com ### What happened? Cosmopolitan Python's `sys.platform` always returns 'linux'. ``` bash-5.2$ ./python Python 3.12.3 (main, Jan 5 2025, 22:22:40) [GCC 14.1.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import sys >>> sys.platform 'linux' >>> ``` ### Version Python 3.12.3 (main, Jan 5 2025, 22:22:40) [GCC 14.1.0] on linux ### What operating system are you seeing the problem on? Mac ### Relevant log output ```shell bash-5.2$ ./python Python 3.12.3 (main, Jan 5 2025, 22:22:40) [GCC 14.1.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import sys, platform >>> sys.platform 'linux' >>> platform.system() 'Darwin' >>> ```