Bug#578004: aspline includes duplicate points in output

[Stuart Prescott <stuart+debian@nanonanonano.net>]

Package: spline
Version: 1.1-11
Severity: important
Tags: pending

The spline package in squeeze/sid (1.1-14) shows duplicated output on i386:

  # aptitude install spline=1.1-11
  $ echo -e "1\n2\n3\n" | aspline -a 1 -n 6
  0 1
  0.333333 1.25926
  0.666667 1.74074
  1 2
  1.33333 2.18519
  1.66667 2.59259

  # aptitude install spline=1.1-14
  $ echo -e "1\n2\n3\n" | aspline -a 1 -n 6
  0 1
  0.333333 1.25926
  0.666667 1.74074
  1 2
  1 2
  1.33333 2.18519
  1.66667 2.59259
  2 3

It turns out that the lenny package will also exhibit this problem if simply
recompiled with the newer gcc that is in lenny -- the version of spline in
lenny was compiled with a much older gcc (gcc-4.1 4.1.2-11):

  $ apt-get source -b spline=1.1-11
  # dpkg -i spline_1.1-11_i386.deb
  $ echo -e "1\n2\n3\n" | aspline -a 1 -n 6
  0 1
  0.333333 1.25926
  0.666667 1.74074
  1 2
  1 2
  1.33333 2.18519
  1.66667 2.59259
  2 3

Thus rendering the package unsafe for binNMUs etc.

The behaviour appears to be arch-dependent and compiler flag dependent.
Disabling optimisation (-O0) solves the problem and it is not seen on amd64 or
PPC. Using -mfpmath=387 on amd64 also causes the erroneous output.

This is fixed in a new upstream version -- inclusion of a build-time test for
this problem seems sensible to test across other architectures.