fix ar invocation on older macs
begnuas: cleanup, use C99
begnuas: cstring section is incorrect with '\0' in the middle of the string
remove the strange/unused concept of mem_pinned.

I don't really understand what it was supposed to do (because nodes
using/producing should be pretty much immovable anyway because of their
dependencies, so an additional pinning type appears unnecessary).
In practice there was no code differentiating between mem_pinned and exc_pinned.
remove exception support for CopyB nodes

CopyB is normally used to transfer data on the stack or to enable compound
value calling conventions. Exceptions don't happen in these cases.
remove InstOf node

This node was used by OO code in the past, but newer versions of liboo
have their own node and don't need it anymore.