code: private void pushExtension(final CLClause c, final int blit) {
          pushExtension(0);
          for (int i = 0; i < c.lits().size(); i++) {
              final int lit = c.lits().get(i);
              if (lit != blit) { pushExtension(lit); }
          }
          pushExtension(blit);
      }
docs: Pushes and logs a clause and its blocking literal to the extension.
  @param c    the clause
  @param blit the blocking literal