main/py-lxml: add py2/py3 subpackages

main/py-lxml/APKBUILD

 # Contributor: Francesco Colista <fcolista@alpinelinux.org>
+# Contributor: Jakub Jirutka <jakub@jirutka.cz>
 # Maintainer: Francesco Colista <fcolista@alpinelinux.org>
 pkgname=py-lxml
 _pkgname=lxml
 pkgver=3.6.0
-pkgrel=0
+pkgrel=1
 pkgdesc="Python LXML Library"
 url="http://lxml.de/"
-arch="all"
+arch="noarch"
 license="BSD"
 depends=""
-makedepends="python-dev libxml2-dev libxslt-dev py-setuptools"
-install=""
+makedepends="python2-dev python3-dev libxml2-dev libxslt-dev py-setuptools"
+subpackages="py2-$_pkgname:_py2 py3-$_pkgname:_py3"
 source="https://files.pythonhosted.org/packages/source/${_pkgname:0:1}/$_pkgname/$_pkgname-$pkgver.tar.gz"
+builddir="$srcdir/$_pkgname-$pkgver"
 
-_builddir="$srcdir"/$_pkgname-$pkgver
 build() {
-	cd "$_builddir"
-	python setup.py build || return 1
+	cd "$builddir"
+	python2 setup.py build || return 1
+	python3 setup.py build
 }
 
 package() {
-	cd "$_builddir"
-	python setup.py install --prefix=/usr --root="$pkgdir" || return 1
+	mkdir -p "$pkgdir"
+}
+
+_py2() {
+	replaces="$pkgname"
+	_py python2
+}
+
+_py3() {
+	_py python3
+}
+
+_py() {
+	local python="$1"
+	pkgdesc="$pkgdesc (for $python)"
+	arch="all"
+	install_if="$pkgname=$pkgver-r$pkgrel $python"
+
+	cd "$builddir"
+	$python setup.py install --prefix=/usr --root="$subpkgdir"
 }
 
 md5sums="5957cc384bd6e83934be35c057ec03b6  lxml-3.6.0.tar.gz"