How can I install two versions of the same software w/o overwriting?

Question

Specifically, I want to install compiz-git without overwriting my current version. I'd like to just run a different command to run the git version.
pkgname=compiz-core-git
pkgver=20090508
pkgrel=1
pkgdesc="Composite manager for Aiglx and Xgl"
url="http://www.compiz-fusion.org/"
license=('GPL' 'LGPL' 'MIT')
arch=('i686' 'x86_64')
depends=('startup-notification' 'librsvg' 'libgl' 'dbus' 'mesa' 'libxslt' 'fuse')
makedepends=('git' 'intltool' 'pkgconfig')
conflicts=('compiz-git' 'compiz-core' 'compiz' 'compiz-decorator-gnome' 'compiz-kde-git')
provides=('compiz-git')
replaces=('compiz-git')
groups=('compiz-fusion-git' 'compiz-git' 'compiz-gtk-git' 'compiz-kde-git')
source=()
md5sums=()
options=(!libtool !emptydirs)
_gitroot="git://git.compiz-fusion.org/compiz/core"
_gitname="compiz"
build() {
msg "Connecting to the GIT server...."
if [[ -d $srcdir/$_gitname ]] ; then
cd $_gitname
git pull origin
msg "The local files are updated."
else
git clone $_gitroot $_gitname
cd $_gitname
git checkout --track -b compiz-0.8 origin/compiz-0.8
fi
msg "GIT checkout done"
msg "Starting make..."
rm -rf $srcdir/$_gitname-build
cp -r $srcdir/$_gitname $srcdir/$_gitname-build
cd $srcdir/$_gitname-build
./autogen.sh \
--prefix=/usr --with-gconf-schema-file-dir=/etc/gconf/schemas \
--enable-librsvg --enable-dbus\
--disable-gconf \
--disable-schemas-install \
--disable-gnome \
--disable-gnome-keybindings \
--disable-gtk \
--disable-metacity \
--disable-kde \
--disable-kde4 \
--disable-kconfig \
--disable-static || return 1
make || return 1
make DESTDIR=$pkgdir install || return 1
rm -rf $srcdir/$_gitname-build

Answer 1

Configure with a different prefix -- perhaps /opt or /usr/local.