*.o files need to be unique within a link image, else the debugger will not properly show symbols from the modules with the name clash.
plot.o was being linked in twice, once as a bitmap.
find.o was being linked in twice, once as a bitmap.

pcbnew: Excellon files use only ascii codes in comments (some excellon parsers do not like I18n)

removed GPC library due to its unacceptable license. Using the great and powerfull kbool library insteed