When I compile a wix project, and wix launch the compilation via MSbuild of all the existing projects, can I use "Any CPU" instead of "X86" or "64 bit" ?
If not, how can I compile the projects using "Any CPU" ?
If your question is whether you can compile WIXPROJ for Any CPU then the answer is no.
"WiX projects will not be built when building the 'Any CPU' platform because Windows Installer packages are CPU-specific."
The TargetPlatform setting in your WIXPROJ defines the way Windows Installer treats folder variables, registries and GAC etc. For example, the setup project will use the [ProgramFiles64Folder] variable if the TargetPlatform of the setup project is x64; and [ProgramFilesFolder] for x86.
Check this answer, it will be helpful: http://windows-installer-xml-wix-toolset.687559.n2.nabble.com/Any-CPU-platform-in-wix-3-0-td3441097.html
Step1: Go to solution Properties
Step2: Configuration properties --> Configuration
Step3: Check the build option for WIX project.
来源：https://stackoverflow.com/questions/21168426/compile-wix-project-using-any-cpu-instead-of-x86