Make mandelbrot.c play nice with older systems
Make mandelbrot.c play nice with older systems

The 'cc' on old unix (e.g. MissPiggy at lcm) doeesn't have stdlib.h.
Also, the '@' character is the KILL character for standard tty input,
resulting in most of the character array being zapped when you read
in papertape.  So let's do without that.

hughpyle/ASR33,hughpyle/ASR33,hughpyle/ASR33,hughpyle/ASR33