Add src/etc/add-authors.sh script for managing the AUTHORS.txt file

This is the kind of dumb task that gets done a different way every
time and is easily automated.

src/etc/add-authors.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+# Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution and at
+# http://rust-lang.org/COPYRIGHT.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+# This script, invoked e.g. "add-authors.sh 1.0.0..rust-lang/master",
+# will merge new authors into AUTHORS.txt, obeying the mailmap
+# file.
+#
+# After running this script, run `git diff` to manually inspect
+# changes. If there are incorrect additions fix it by editing
+# .mailmap and re-running the script.
+
+set -u -e
+
+range="$1"
+
+authors_file="./AUTHORS.txt"
+tmp_file="./AUTHORS.txt.tmp"
+old_authors="$(cat "$authors_file" | tail -n +2 | sed "/^$/d" | sort)"
+new_authors="$(git log "$range" --format="%aN <%aE>" | sort | uniq)"
+
+echo "Rust was written by these fine people:\n" > "$tmp_file"
+echo "$old_authors\n$new_authors" | sort | uniq >> "$tmp_file"
+mv -f "$tmp_file" "$authors_file"