Problem with texinfo 5.0 package

[Mark H Weaver <mhw@netris.org>]

Hi Ludovic,

Regarding commit a24b75d8e1753da629ecf945f4022eee4c340aed:

The built texinfo 5.0 packages contain a few uses of 'perl' that are not
pointing to a specific version in /nix/store:

./bin/pod2texi:1:#!/nix/store/777jas1fcgc38hmvq6lq1sa9k67f10kl-coreutils-8.20/bin/env perl
./bin/texi2dvi:1437:      perl -pe 's<\\documentclass(?:\[.*\])?{.*}>
./bin/texi2dvi:1544:      perl -pi -e 's/[ \t]+$//g' "$out_base"*;;
./bin/texi2any:1:#!/nix/store/777jas1fcgc38hmvq6lq1sa9k67f10kl-coreutils-8.20/bin/env perl 

    Regards,
      Mark