The IDE now provides the following project properties to make it easier for you to use unmanaged projects in version control systems.
You can provide a list of macros (–D options) that are volatile. They depend on time, date, or specific environment. These macros environment variable values will not be stored with the project's public metadata.
You can provide a list of environment variables that the project uses to pass system-specific paths. These macros environment variable values will not be stored with the project's public metadata. For unmanaged projects, you can specify the list of environment variables to be used when storing project metadata. When the IDE stores the compiler options and an option value coincides with a variable value, a macros will be written instead.