386 system call fixes:

386 system call fixes:
  * use 64-bit file system calls (Linux, Darwin)
  * use 32-bit [sic] uid/gid calls (Linux)
  * fix sockets on Linux

Darwin/386 works again.

Linux/386 is better but must never have worked;
there are still bugs surrounding the creation of new
threads in the runtime package.

R=austin
DELTA=1332  (673 added, 614 deleted, 45 changed)
OCL=30327
CL=30380