see if we can guess the #bytes until the end of the file.  If we
can't, increment the buffer size increments up to 0.5Meg to avoid
realloc'ing too much.

Infinite failure stack, some bugs fixed (fastmap, star_jump, register bug).

Document how to get exit status of a popen() command.

behind the shell window on NT.

symbols is needed, define these in Python.h with a Py_ prefix.