first attempt at real FFI support.

first attempt at real FFI support.

in a .6 file, an export line

	//ffi T localfib remotefib remote.so

means the dynamic linker should initialize
localfib, always a pointer, to the address of
remotefib, either text (T) or data (D) after
loading remote.so.

the C compiler will generate an export section
when given the pragmas

	#pragma package fib
	#pragma ffi T localfib remotefib remote.so

needing #pragma package is a bit of a kludge
and hopefully could go away later.

this is just the 6 tool chain support.
other architectures will happen once 6 settles down.

code using this to do FFI is in a later CL.

R=r
DELTA=161  (141 added, 14 deleted, 6 changed)
OCL=33783
CL=33795