This option controls when the compiler will issue messages for conversions
that will be done via a library call.

.-*---.
>>-MSG--(--+-390-+--)------------------------------------------><
- *
- Causes the compiler to issue warning messages for conversions that will
be done via a library call if and only if they would be done via a library
call on the platform where the code is compiled.
- 390
- Causes the compiler to issue warning messages for conversions that will
be done via a library call if and only if they would be done via a library
call on 390.