Add a Makefile for the git-auth wrapper

Avoid manual editing of the wrapper script when a non-standard path is
used.

Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>

INSTALL

@@ -34,8 +34,7 @@ Setup on Arch Linux
 7) Install the git-auth wrapper script:
 
     # cd /srv/http/aurweb/git-interface/
-    # cp git-auth.sh /usr/local/bin/aur-git-auth
-    # chmod 755 /usr/local/bin/aur-git-auth
+    # make && make install
 
 8) Configure sshd(8) for the AUR. Add the following lines at the end of your
    sshd_config(5) and restart the sshd. Note that OpenSSH 6.9 or newer is

git-interface/Makefile

+GIT_INTERFACE_DIR := $(abspath $(dir $(lastword $(MAKEFILE_LIST))))
+
+include config.mk
+
+git-auth.sh:
+	sed 's#%GIT_INTERFACE_DIR%#$(GIT_INTERFACE_DIR)#' <git-auth.sh.in >git-auth.sh
+	chmod +x git-auth.sh
+
+install: git-auth.sh
+	install -Dm0755 git-auth.sh "$(DESTDIR)$(PREFIX)/bin/aur-git-auth"
+
+uninstall:
+	rm -f "$(DESTDIR)$(PREFIX)/bin/aur-git-auth"
+
+clean:
+	rm -f git-auth.sh
+
+.PHONY: install uninstall clean

git-interface/config.mk

+PREFIX = /usr/local

git-interface/git-auth.sh

-#!/bin/sh
-
-/srv/http/aurweb/git-interface/git-auth.py "$1" "$2"

git-interface/git-auth.sh.in

+#!/bin/sh
+
+%GIT_INTERFACE_DIR%/git-auth.py "$1" "$2"