The no-longer available versions of CodeWarrior Pro for desktop development allowed you to develop for both Macintosh and Windows platforms. The "host" is the computer's OS used to run the CodeWarrior tools. In this case, it happens to be Solaris. If you were writing for the Windows platform, the minimum requirements info you mentioned specifies the type of system necessary to run the Windows app you developed.
That's the historic perspective. The current situation is that Freescale has discontinued development and support of the desktop product for several years.
---Tom