Just downloaded and tried Visual Studio 2012(with update 2, version 11.0.60315.01). The Windows XP targeting is available(actually already available in update 1):

 photo vs2012_xp_target_zps10d34c42.png

The executable generated by the original VS2012 toolchain does not run under Windows XP. A error message box is shown:

 photo vs2012_xp_target_2_zpsc799786a.png

In update 1, the static and dynamic link libraries for the CRT, STL and MFC have been updated in-place to add runtime support for Windows XP and Windows Server 2003. And the runtime version is upgraded to 11.0.51106.1 from 11.0.50727.1.

Except the library update, there’s none real difference when selecting “v110” or “v110_xp” toolchain. I wrote a simple HelloWorld application and compare the two generated binary.

And the output:

The first difference represents the timestamps of the two binary. The other two differences standard for “Operating System Version” and “Subsystem Version”. We have 5.1 for Windows XP, 6.0 for Windows Vista and later. That’s all. And we can easily build a Windows XP binary from the command line with only one additional linker switch:

I also built a simple MFC application(dynamic link to MFC) with Windows XP target in VS2012. It runs fine under Windows XP with MFC DLLs copied in the same directory. From VS2010, the SxS assembly is not used any more. All you need to do is copy the dependent DLLs to the application directory and run.

Reference: http://blogs.msdn.com/b/vcblog/archive/2012/10/08/10357555.aspx