OpenBSD fixes and updates

I forgot how awful the process name logic was. It was an initial hack to
get it running, and I forgot to clean it up.

I also had to change a few includes and error function uses.

openbsd/Platform.h

@@ -11,6 +11,7 @@ in the source distribution for its full text.
 */
 
 #include "Action.h"
+#include "SignalsPanel.h"
 #include "BatteryMeter.h"
 
 extern ProcessFieldData Process_fields[];