Added OSX install instructions

README.md

@@ -22,6 +22,74 @@ Linux and Mac users will have to compile the source code themselves.
 <a href="https://jenkins.libtoxcore.so/job/tux3-toxgui-win32/lastSuccessfulBuild/artifact/toxgui-win32.zip">Windows download</a><br/>
 <a href="http://speedy.sh/XXtHa/toxgui">Linux download (1st July 2014 01:30 GMT)</a><br/>
 Note that the Linux download has not been tested.
+<br/>
+
+<h3>OSX Install Guide</h3>
+
+<strong>This guide is intended for people who wish to use an existing or new ProjectTox-Core installation separate to the bundled installation with toxgui, if you do not wish to use a separate installation you can skip to the section titled 'Final Steps'.</strong>
+
+Installation on OSX, isn't quite straight forward, here is a quick guide on how to install;
+
+The first thing you need to do is install ProjectTox-Core with a/v support. Refer to the INSTALL guide in the ProjectTox-Core github repo.
+
+Next you need to download QtTools (http://qt-project.org/downloads), at the time of writing this is at version 5.3.0.
+Make sure you deselect all the unnecessary components from the 5.3 checkbox (iOS/Android libs) otherwise you will end up with a very large download.
+
+Once that is installed you will most likely need to set the path for qmake. To do this, open up terminal and paste in the following;
+
+```bash
+export PATH=/location/to/qmake/binary:$PATH
+```
+
+For myself, the qmake binary was located in /Users/mouseym/Qt/5.3/clang_64/bin/.
+
+Once this is installed, do the following;
+
+```bash
+git clone https://github.com/tux3/toxgui
+cd toxgui
+qmake
+```
+
+Do not run make, as we need further modifications to toxgui.
+
+Open up the Makefile in a text editor (TextEdit/TextWrangler, etc).
+
+You will need to modify the Makefile to point to your toxcore libs/includes.
+
+The first change you will need to make is to point the Makefile towards the tox libs installed on your system. (Generally this is /usr/local/libs/).
+
+Look for the line in the Makefile which references /toxgui/lib/libs/ and replace with the above).
+
+The second change to Makefile is to add the location of the includes (On my system these were placed in /usr/local/include/tox/).
+
+To do this, search for the INCLUDES line and add the following to the end;
+
+```bash
+-I/usr/local/include/tox/
+```
+
+Save the Makefile.
+
+<h4>Final Steps</h4>
+
+Open up TextEdit/TextWrangler/etc and open up the widget/filetransfertwidget.cpp file and add the following include;
+
+```bash
+#include <math.h>
+```
+
+This will stop toxgui failing to make under OSX.
+
+The final step is to run 
+```bash
+make
+``` 
+in the toxgui directory, or if you are using the bundled tox core installation, you can use 
+```bash
+./bootstrap.sh
+```
+Assuming all went well you should now have a toxgui.app file within the directory. Double click and it should open!
 
 <h3>Screenshots</h3>
 <h5>Note: The screenshots may not always be up to date, but they should give a good idea of the general look and features</h5>