o Back out the __std* stuff. Can't figure out how to do this right now,
so we'll save it for late.
o use _up as a pointer for extra fields that we need to access.
o back out the libc major version bump.
Submitted by: green
reviewed by: peter, imp, green, obrien (to varying degrees).
We'll fix the "how do we stop encoding sizeof(FILE) in binaries" part
later.
51cffb6bac