Fix a problem with character after comment always added to macro definition

This was especially problematic if the line ended with the comment,
since then the next line would be added, too, even though the current
one didn't end with a '\'

Author: usiems

generator/parser/rpp/pp-engine-bits.h

@@ -621,8 +621,13 @@ InputIterator pp::handle_define (InputIterator _first, InputIterator _last)
   while (_first != _last && *_first != '\n')
     {
       if (*_first == '/') {
+          const InputIterator _before = _first;
           _first = skip_comment(_first, _last);
           env.current_line += skip_comment.lines;
+          if (_first != _before) {
+              // do not indiscriminately add the character after comment
+              continue;
+          }
       }
 
       if (*_first == '\\')