Log Message:
Update to 4.10, based on pkgsrc/wip/nspr by mef@.

* Set LICENSE.

Changelog:
http://mozilla.6506.n7.nabble.com/ANNOUNCE-NSPR-4-10-Release-td280660.html
--------------
  NSPR 4.10 has the following bug fixes:
* Bug 331169: Obviate PR_Sleep before PR_GetConnectStatus on Windows.
  Fixed by Brian Smith.
* Bug 687033: Support Windows/arm. Fixed by Makoto Kato (partially
  checked in).
* Bug 687033: Remove WINCE and Win9x support partially.
* Bug 844513: Add AddressSanitizer (ASan) memory check annotations to
  PLArena. Fixed by Mats Palmgren.
* Bug 849089: Simple changes to make NSPR's configure.in work with
  the current version of autoconf.
* Bug 856196: Fix compiler warnings and clean up code in NSPR 4.10.
* Bug 859066: Fix warning in nsprpub/pr/src/misc/prnetdb.c.
* Bug 859830: Deprecate ANDROID_VERSION in favor of android/api-level.h.
  Fixed by Vicamo Yang.
* Bug 861434: Make PR_SetThreadPriority() change priorities
  relatively to the main process instead of using absolute values on
  Linux. Fixed by Gabriele Svelto.
* Bug 871064L: _PR_InitThreads() should not call PR_SetThreadPriority.