Which file in brl.mod/system.mod is the compile error reported? You shouldn't have to amend the official modules as they should already have the relevant directives.
Did you install BlitzMax by installing v1.18, and then use the *Mac* v1.28 PPC update? Did you run syncmods after installing the patch?
It sounds like you might have got some Windows files in your Mac BlitzMax folder, so you'll need to provide more more details, such as which version of BRL.System you are using (written at the top of brl.mod/system.mod/system.bmx).
Did you install BlitzMax by installing v1.18, and then use the *Mac* v1.28 PPC update? Did you run syncmods after installing the patch?
It sounds like you might have got some Windows files in your Mac BlitzMax folder, so you'll need to provide more more details, such as which version of BRL.System you are using (written at the top of brl.mod/system.mod/system.bmx).