o Not all derived methods were marked 'override', but it is a great
feature of C++11 that we should make use of.
o While at it: touched header files got a -*- c++ -*- for emacs to
provide support for that language.
o use YS_OVERRIDE for all override keywords (though we should probably
use the plain keyword going forward now that C++11 is established)
This is easily triggered when un-techmapping if the technology-specific
cell library isn't loaded. Outputs of technology-specific cells will be
seen as inputs, and nets using those outputs will be seen as undriven.
Just ignore these cells because they can't be part of a reduce chain
anyways.
Clifford Wolf
Henner Zeller
Andrew Zonenberg
Robert Ou