New MPIR won't build on Cygwin

Imported from <a href="http://trac.sagemath.org/sage_trac/ticket/12115">trac #12115</a>.

Spkg diff, for review only.

Reported by: kcrisman

Component: cygwin

CC: leif,, dimpase,, wbhart,, jdemeyer

Report Upstream: None of the above - read trac for reasoning.

Authors: 

Dependencies: 

Work issues: 

Reviewers: Volker Braun, Karl-Dieter Crisman, Jean-Pierre Flori

Merged in: 

Attachments: <ol><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12115/draft-of-diff-mpir-2.1.3.p7-p8.diff">draft-of-diff-mpir-2.1.3.p7-p8.diff: For reference only - don't build static library</a> by kcrisman at 20111203T21:32:03</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12115/mpir-2.4.0.p5.log">mpir-2.4.0.p5.log: </a> by jpflori at 20120711T08:25:19</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12115/mpir-2.5.1.p1.log">mpir-2.5.1.p1.log: </a> by jpflori at 20120711T08:25:55</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12115/mpir-2.4.0.p6.log">mpir-2.4.0.p6.log: </a> by jpflori at 20120711T08:28:10</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12115/spkg.diff">spkg.diff: Spkg diff, for review only.</a> by jpflori at 20120801T12:56:04</li></ol>