You do not need gg: to use FPC. It comes with every tool you need. It's handly to have GG:, especially if you want to recompile the compiler itself, but for basic use, you don't need it.

About that libc unit thing, i already had some pain with it, while fixing some code for PPC. It's some x86 only unit, for Delphi/Kylix compatibility, and never will be available on systems other than x86, IIRC. But it's not that hard to port code to use FPC equivalent calls, or to make a wrapper libc unit for these calls.