Add 'linesource', to contain the path/file of the origin of the line.

src/include/ngspice/inpdefs.h

@@ -77,6 +77,7 @@ struct card_assoc {
 struct card {
     int linenum;
     int linenum_orig;
+    char* linesource;
     char *line;
     char *error;
     struct card *nextcard;