Upgrade MPIR to a more recent upstream release

Imported from <a href="http://trac.sagemath.org/sage_trac/ticket/11616">trac #11616</a>.

Diff between the 2.4.0.p2 and 2.4.0.p3 spkgs. For reference / review only.

Reported by: leif

Component: packages

CC: justin,, wbhart,, jpflori

Report Upstream: N/A

Authors: Leif Leonhardy, Jeroen Demeyer

Dependencies: 

Work issues: 

Reviewers: Jeroen Demeyer, Leif Leonhardy, Volker Braun

Merged in: sage-5.0.rc0

Attachments: <ol><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/11616/MPIR_upstream_changes_between_2.1.1_and_2.4.0.txt">MPIR_upstream_changes_between_2.1.1_and_2.4.0.txt: Note that some changes between 2.1.1 and 2.1.4 may be missing (documented elsewhere, i.e. at least on `mpir-devel` I think). The segfault was fixed in 2.1.3, the race condition in 2.1.4.</a> by leif at 20110722T07:49:29</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/11616/mpir-2.1.3.p9-2.4.0.p1.diff">mpir-2.1.3.p9-2.4.0.p1.diff: Diff between the previous spkg in Sage and my new p1 spkg.  For reference / review only.</a> by leif at 20120405T15:02:32</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/11616/mpir-2.4.0.p1-p2.diff">mpir-2.4.0.p1-p2.diff: Diff between the 2.4.0.p1 and 2.4.0.p2 spkgs. For reference / review only. </a> by jdemeyer at 20120410T12:43:22</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/11616/mpir-2.4.0.p2-p3.diff">mpir-2.4.0.p2-p3.diff: Diff between the 2.4.0.p2 and 2.4.0.p3 spkgs. For reference / review only.</a> by jdemeyer at 20120429T14:06:11</li></ol>