/Y- (Ignore Precompiled Header Options)
Causes all other /Y compiler options to be ignored (and cannot itself be overridden).
For more information on precompiled headers, see:
To set this compiler option in the Visual Studio development environment
Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.
Click the C/C++ folder.
Click the Command Line property page.
Type the compiler option in the Additional Options box.
To set this compiler option programmatically