Documents various git issues for Windows.
diff --git a/docs/howto_SDK_git_cygwin.txt b/docs/howto_SDK_git_cygwin.txt
new file mode 100644
index 0000000..2f890a3
--- /dev/null
+++ b/docs/howto_SDK_git_cygwin.txt
@@ -0,0 +1,165 @@
+Copyright (C) 2009 The Android Open Source Project
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+
+Subject: How to get the android source code using Cygwin and Git
+Date: 2009/04/27
+
+
+
+Table of content:
+ 1- Goals and Requirements
+ 2- Getting the code, the simple way
+ 3- SSH issues
+ 4- Advanced Tricks
+
+
+-------------------------
+1- Goals and Requirements
+-------------------------
+
+This document explains how to checkout the Android source from the git
+repositories under Windows.
+
+As stated in development/docs/howto_build_SDK.txt, one can't build the whole
+Android source code under Windows. You can only build a the SDK tools for
+Windows.
+
+There are a number of caveats in checking out the code from Git under Windows.
+This document tries to explain them.
+
+First you will need to meet the following requirements:
+- You must have Cygwin installed.
+ See http://www.cygwin.com/
+
+- You must install Cyginw using the "Unix / Binary" mode.
+ If you don't do that, git will fail to properly compute some SHA1 keys.
+
+- You need the "git" and "curl" packages to checkout the code.
+ If you plan to contribute, you might want to get "gitk" also.
+
+ Note: if you want to build the SDK, check the howto_build_SDK.txt file
+ for a list of extra required packages.
+
+
+-----------------------------------
+2- Getting the code, the simple way
+-----------------------------------
+
+Out of the box, "repo" and "git" will work just fine under Cygwin:
+
+ $ repo init -u git://android.git.kernel.org/platform/manifest.git
+ $ repo sync
+
+And you're done. You can build as explained in howto_build_SDK.txt and ignore
+the rest of this document.
+
+
+-------------
+3- SSH issues
+-------------
+
+If you maintain your own private repository using an SSH server, you might get
+some "mux/ssh" errors. In this case try this:
+
+ $ repo init -u ssh://my.private.ssh.repo/platform/manifest.git
+ $ export GIT_SSH=ssh
+ $ repo sync
+
+
+------------------
+4- Advanced Tricks
+------------------
+
+There are two remaining issues with the default repo/git options:
+
+A- If you plan on contributing, you will notice that even after a fresh "repo
+sync" some projects are marked as having modified files. This happens on the
+"bionic" and the "external/iptables" project. The issue is that they have files
+which have the same name yet differ only by their case-sensitivity. Since the
+Windows filesystem is not case-sensitive, this confuses Git.
+
+Solution: we can simply ignore these projects as they are not needed to build
+the Windows SDK.
+
+To do this you just need to create a file .repo/local_manifest.xml that
+provides a list of projects to ignore:
+
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest>
+ <remove-project name="platform/bionic" />
+ <remove-project name="platform/external/iptables" />
+</manifest>
+
+
+B- The other issue is that by default repo maintains around 100+ git projects.
+However most of these are not needed to build the Windows SDK. We can easily
+reduce this list to around 60 projects, which will make your repo syncs a lot
+faster.
+
+Solution: Simply ignore all projects bionic, bootable/*, external/* and
+hardware/*.
+
+Here's a script that takes care of all these details. It performs the repo
+init, creates the appropriate local_manifest.xml and does a repo sync as
+needed:
+
+------------
+#!/bin/bash
+
+set -e # fail on errors
+
+URL=git://android.git.kernel.org/platform/manifest.git
+BRANCH=donut
+
+if [ ! -d .repo ]; then
+ # repo init if there's no .repo directory
+ repo init -u $URL -b $BRANCH
+
+ # create a local_manifest to exclude projects not useful to the Windows SDK
+ M=.repo/manifest.xml
+ L=.repo/local_manifest.xml
+
+ cat > $L <<EOF
+<?xml version="1.0" encoding="UTF-8"?>
+<manifest>
+EOF
+
+ for i in $(grep -E "/(bionic|bootable|external|hardware)" $M | sed -s '/name/s/^.*name="\([^"]\+\)".*/\1/') ; do
+ echo "Ignore project $i"
+ echo " <remove-project name=\"$i\" />" >> $L
+ done
+
+ cat >> $L <<EOF2
+</manifest>
+EOF2
+fi
+
+[[ $URL != ${URL/ssh/} ]] && export GIT_SSH=ssh
+repo sync
+------------
+
+
+Simply extract this to a "my_sync.sh" file and try the following:
+ $ mkdir android_src
+ $ cd android_src
+ $ chmod +x mysync.sh
+ $ ./mysync.sh
+
+
+-end-
+
+
+
+