--gnu_version=version

Where version is a decimal number denoting the version of GCC that you are attempting to make the compiler compatible with.

This option is for when GNU compatibility mode is being used.

This option is for expert use. It is provided for dealing with legacy code. You are not normally required to use it.

In RVCT v4.0, the default is 40200. This corresponds to GCC version 4.2.0.

--gnu_version=30401 makes the compiler compatible with GCC 3.4.1 as far as possible.