Modified the Makefile to allow the user to choose the OPTDEBUGFLAGS using environment variables. Also allows to define base CXXFLAGS.
Modified the Makefile to allow the user to choose the OPTDEBUGFLAGS using
environment variables.
Also allows to define base CXXFLAGS.

SymbiFlow/arachne-pnr,cseed/arachne-pnr,SymbiFlow/arachne-pnr,SymbiFlow/arachne-pnr,cseed/arachne-pnr,cseed/arachne-pnr