Fix potential xterm size exception
Fix potential xterm size exception

depending on vertical size of xterm and number of builders, the variable
log size could be negative.  Rather than allow this, set the minimum log
size to 10 lines and let ncurses handle the overflow invisibly (which
handles later resizing)

jrmarino/synth,jrmarino/synth,jrmarino/synth,jrmarino/synth