OK, there's at least one application author who has provided dynamic locking

 Changes between 0.9.6h and 0.9.7  [XX xxx 2002]

  *) The hw_ncipher.c engine requires dynamic locks.  Unfortunately, it

     seems that in spite of existing for more than a year, no application

     author has done anything to provide the necessary callbacks, which

     seems that in spite of existing for more than a year, many application

     author have done nothing to provide the necessary callbacks, which

     means that this particular engine will not work properly anywhere.

     This is a very unfortunate situation which forces us, in the name

     of usability, to give the hw_ncipher.c a static lock, which is part