[ANNOUNCE] NSPR 4.22 Release

The NSPR 4.22 release is now available.  The hg tag is
NSPR_4_22_RTM.  The source tar file can be downloaded from
https://ftp.mozilla.org/pub/mozilla.org/nspr/releases/v4.22/src/

NSPR 4.22 contains the following changes:
- added support for the ARC architecture
- removed support for the following platforms:
  OSF1/Tru64, DGUX, IRIX, Symbian, BeOS
- correctness and build fixes

For details, please refer to the list of related bugs:
https://bugzilla.mozilla.org/buglist.cgi?resolution=FIXED&query_format=advanced&product=NSPR&target_milestone=4.22

Thanks to all contributors to this release.
Kai