Add PKGBUILD for Arch Linux users

package/.gitignore

@@ -0,0 +1,3 @@
+*
+!.gitignore
+!PKGBUILD

package/PKGBUILD

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+# Maintainer: Kim Silkebækken <kim.silkebaekken+aur@gmail.com>
+
+pkgname=powerline-git
+pkgver=20121217
+pkgrel=1
+pkgdesc='The ultimate statusline/prompt utility.'
+url='https://github.com/Lokaltog/powerline'
+license=('CC BY-SA 3.0')
+arch=('any')
+depends=('vim' 'python2>=2.7')
+makedepends=('git')
+source=()
+
+_gitroot="git://github.com/Lokaltog/powerline.git"
+_gitname="powerline"
+_gitbranch="develop"
+
+build() {
+	cd ${srcdir}
+
+	msg "Connecting to GitHub..."
+
+	if [ -d ${srcdir}/${_gitname} ]; then
+		cd ${_gitname} && git pull origin ${_gitbranch}
+		msg "The local files are updated."
+	else
+		git clone ${_gitroot}
+		git checkout ${_gitbranch}
+	fi
+
+	msg "Git checkout done or server timeout."
+
+	cd ${srcdir}/${_gitname}
+
+	python2 setup.py build || return 1
+	python2 setup.py install --root=${pkgdir} || return 1
+}