I was just able to build the IE driver components using Visual Studio 2012 without any difficulty. Here's what I did:
- Open the solution in the root of the git clone (recommended over downloading a zip)
- Right-click on the solution in the Solution Explorer window and select "Update VC++ projects" and click Update on the confirmation dialog
- Right-click on the solution again, and select "Configuration Manager..."
- In the Configuration Manager dialog, select either "Win32" or "x64" in the "Active solution platform" dropdown, and click the Close button (sets the platform for which to build)
- Right-click on the IEDriverServer project in the Solution Explorer window and click "Build"
Some caveats. First, you must select the appropriate platform. By default, the selected platform won't properly build the dependent projects. Also, don't just try to build the solution; make sure you're only building the IE projects. The Firefox C++ projects are statically linked to .lib files from the Gecko SDK provided by Mozilla, but the .libs were build using Visual Studio 2010, so the Firefox projects won't link under Visual Studio 2012 or 2013.
Please note that building under any version of Visual Studio other than 2010 is strictly unsupported. This may or may not work completely for you.
--Jim