Version 0.2.21

* Add many more socket related constants
* Fix i686 and aarch64 android
* Add many more termios related constants/functions
* Add ppoll
* Add readdir for more platforms
* Add jail functions/constants for FreeBSD
* Add pthread_exit
* Add EPOLLEXCLUSIVE
* Add WIFCONTINUED
* Add MSG_PEEK
* Fix a number of issues on Solaris
* Add wcstombs
* Add O_TMPFILE
* Add pipe2 to more platforms
This tag has no release notes.