dev-libs/nspr: version bump to 4.12

dev-libs/nspr: version bump to 4.12

Upstream release notes:
* added a PR_GetEnvSecure function, which attempts to detect if the program
  is being executed with elevated privileges, and returns NULL if detected.
  It is recommended to use this function in general purpose library code.

* fixed a memory allocation bug related to the PR_*printf functions

* exported API PR_DuplicateEnvironment, which had already been added in
  NSPR 4.10.9

* added support for FreeBSD aarch64

* several minor correctness and compatibility fixes

Package-Manager: portage-2.2.26