cmake HAVE_IO examples

mariokonrad/marnav examples/library/CMakeLists.txt :14 

target_compile_definitions(foobar PRIVATE HAVE_IO)

mariokonrad/marnav src/nmeatool/CMakeLists.txt :31 

target_compile_definitions(nmeatool
	PRIVATE
		$<$<BOOL:${support_for_io}>:HAVE_IO>
	)