Build: Eliminate Cygwin packaging support

We haven't provided official Cygwin builds since 1.4.x, since Cygwin
now supplies its own libjpeg-turbo packages (although they apparently
haven't been updated past 1.5.3.)

release/makecygwinpkg.in

@@ -1,66 +0,0 @@
-#!/bin/sh
-
-set -u
-set -e
-trap onexit INT
-trap onexit TERM
-trap onexit EXIT
-
-TMPDIR=
-
-onexit()
-{
-	if [ ! "$TMPDIR" = "" ]; then
-		rm -rf $TMPDIR
-	fi
-}
-
-safedirmove ()
-{
-	if [ "$1" = "$2" ]; then
-		return 0
-	fi
-	if [ "$1" = "" -o ! -d "$1" ]; then
-		echo safedirmove: source dir $1 is not valid
-		return 1
-	fi
-	if [ "$2" = "" -o -e "$2" ]; then
-		echo safedirmove: dest dir $2 is not valid
-		return 1
-	fi
-	if [ "$3" = "" -o -e "$3" ]; then
-		echo safedirmove: tmp dir $3 is not valid
-		return 1
-	fi
-	mkdir -p $3
-	mv $1/* $3/
-	rmdir $1
-	mkdir -p $2
-	mv $3/* $2/
-	rmdir $3
-	return 0
-}
-
-PKGNAME=@PKGNAME@
-VERSION=@VERSION@
-BUILD=@BUILD@
-
-PREFIX=@CMAKE_INSTALL_PREFIX@
-DOCDIR=@CMAKE_INSTALL_FULL_DOCDIR@
-LIBDIR=@CMAKE_INSTALL_FULL_LIBDIR@
-
-umask 022
-rm -f $PKGNAME-$VERSION-$BUILD.tar.bz2
-TMPDIR=`mktemp -d /tmp/ljtbuild.XXXXXX`
-__PWD=`pwd`
-make install DESTDIR=$TMPDIR/pkg
-if [ "$PREFIX" = "@CMAKE_INSTALL_DEFAULT_PREFIX@" -a "$DOCDIR" = "@CMAKE_INSTALL_DEFAULT_PREFIX@/doc" ]; then
-	safedirmove $TMPDIR/pkg$DOCDIR $TMPDIR/pkg/usr/share/doc/$PKGNAME-$VERSION $TMPDIR/__tmpdoc
-	ln -fs /usr/share/doc/$PKGNAME-$VERSION $TMPDIR/pkg$DOCDIR
-fi
-cd $TMPDIR/pkg
-tar cfj ../$PKGNAME-$VERSION-$BUILD.tar.bz2 *
-cd $__PWD
-mv $TMPDIR/*.tar.bz2 .
-
-exit 0