SWI Prolog make script

#!/usr/bin/perl

$|++;

$VER="5.8.0";

# --- download src
$URL="http://www.swi-prolog.org/download/stable/src/pl-$VER.tar.gz";
$SRC="pl-$VER";
$TGZ="$SRC.tar.gz";

warn $URL;

`wget $URL` unless -e $TGZ;


# --- unpack src

unless (-e $SRC && -d $SRC) { `tar xvfz $TGZ`; }

# --- create proper src dir for cygwin
$REL=1;
$NEW="SWI-Prolog-$VER-$REL-src";

`mv $SRC $NEW`;

# --- tar and bzip source code
$TAR="$NEW.tar";

`tar cvf $TAR $NEW`;
`bzip2 $TAR`;