And reducing the time taken by my_atomic-t.


include/lf.h:
  fix to be able to add a ";" at the end of the macro's invokation
  (removing it here, removes a warning from "gcc -ansi" about a
  standalone ";").
mysys/lf_hash.c:
  ";" is ok now after LF_REQUIRE_PINS
mysys/mf_pagecache.c:
  comment fix
unittest/mysys/my_atomic-t.c:
  decreasing number of iterations to make test take less time.