Modified the shadow signal conversion code to check if the concatenated signals are driven. If one of the concatenated signal is not driven it now warns and uses the init val of that signal as a constant.
Modified the shadow signal conversion code to check if the concatenated signals are driven. If one of the concatenated signal is not driven it now warns and uses the init val of that signal as a constant.

hgomersall/myhdl,hgomersall/myhdl,hgomersall/myhdl