fix line counting for inner macro expansions (one macro inside another one)

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@8807 626c5289-ae23-0410-ae9c-e8d60b6d4f22

SWIG/Source/CParse/cscanner.c

@@ -75,10 +75,10 @@ static void
 scanner_locator(String *loc) {
   if (Equal(loc,"@SWIG@"))  {    
     /* End locator. */
-    expanding_macro = 0;
+    if (expanding_macro) --expanding_macro;
   } else {
     /* Begin locator. */
-    expanding_macro = 1;
+    ++expanding_macro;
   }
 }