todo

Path MPICH-V for MPICH the MPI Implementation

-FIXMEs in signals.c
-limits
-U __errno_location@@GLIBC_2.0 in libsaferestart.so
-add script to makefile for checking whether safe library has any undefined references.
-compile with PIC?
-linux realtime signals (they appear to be set by telnet).
-Fix the handling of the stack segment

-explain why we have restart.script
 (it lets us load the code a bit lower than
 usual to ensure that the brk does not break.)
 also, clean it up so it is portable and manageable.