fix line number tracking

main.leg

@@ -1,6 +1,6 @@
 # main.leg -- C parser + interpreter
 #
-# Last edited: 2025-02-03 10:47:46 by piumarta on xubuntu
+# Last edited: 2025-02-03 11:58:41 by piumarta on xubuntu
 
 %{
 ;
@@ -1738,7 +1738,7 @@ void startInput(char *name)
 
 void endInput(void)
 {
-    if (List_size(lines)) {
+    if (lines && List_size(lines)) {
 	lineNo = _integerValue(List_popLast(lines));
 	List_popLast(names);
     }

test.txt

@@ -142,8 +142,6 @@ int main(int argc, char **argv)
 
     printf("passed\n");
 
-    float f = 42;
-
     return 0;
 }