Fix (a single) hardcoded 'g++' in Singular 3-1-3-3

Imported from <a href="http://trac.sagemath.org/sage_trac/ticket/12680">trac #12680</a>.

This is the new patch to upstream.  For reference / review only.

Reported by: leif

Component: packages

CC: AlexanderDreyer,, malb,, rohana

Report Upstream: Completely fixed; Fix reported upstream

Authors: Leif Leonhardy

Dependencies: 

Work issues: 

Reviewers: R. Andrew Ohana

Merged in: sage-5.0.beta9

Attachments: <ol><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12680/singular-3-1-3-3.p5-p6.diff">singular-3-1-3-3.p5-p6.diff: Diff between the p5 and my p6. For reference / review only.</a> by leif at 20120317T10:55:36</li><li><a href="http://trac.sagemath.org/sage_trac/attachment/ticket/12680/factory.GNUmakefile.in.patch">factory.GNUmakefile.in.patch: This is the new patch to upstream.  For reference / review only.</a> by leif at 20120317T11:34:33</li></ol>