archlinux: Add make aur target

This is a very simple AUR helper.

Usage: make aur package=<package>

.archlinux/Makefile

@@ -2,6 +2,18 @@
 install:
 	@cd PKGBUILDs/${package} && makepkg -scif --noconfirm
 
+.ONESHELL:
+aur:
+	@mkdir -p .aur && cd .aur
+	@git clone "https://aur.archlinux.org/${package}.git"
+	@cd ${package}
+	@echo "==================================== Viewing ${package}"
+	@cat PKGBUILD
+	@echo "===================================="
+	@echo -n "Press enter to continue, or Ctrl+C to quit. " && read
+	@makepkg -sc
+	@sudo pacman -U *.pkg.tar.xz
+
 .PHONY: update-keys
 update-keys:
 	@sudo pacman-key --populate
@@ -14,3 +26,4 @@ clean:
 	@rm -fv **/*.tar.gz
 	@rm -fv **/*.tar.bz2
 	@rm -fv **/*.vim
+	@rm -rfv .aur