Ok, to main.cpp, I add a line "int i=0; "and recompiled. When I hit the recompile again it said "nothing to be done."
aha!
I deleted the line, and it behaved correctly.
It has behaved correctly ever since.
ALSO, for the first time it created a .depend file.
So, the moral of the story...
choke your chicken.. no, no not that one.
Modify the file until you get a .depend file. Or some such voodoo.