Ensure that libraries link to the shared version of NTL by default

Imported from <a href="http://trac.sagemath.org/sage_trac/ticket/11635">trac #11635</a>.

Spkg diff, for review only.

Reported by: kcrisman

Component: cygwin

CC: mhansen,, dimpase,, jpflori,, jdemeyer

Report Upstream: N/A

Authors: Jean-Pierre Flori

Dependencies: 

Work issues: 

Reviewers: Karl-Dieter Crisman

Merged in: sage-5.6.beta3

Attachments: <ol><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/11635/ntl-5.5.2.p0.diff">ntl-5.5.2.p0.diff: Spkg diff, for review only.</a> by jdemeyer at 20130104T08:10:47</li></ol>