Let MySQL check the existence of readdir_r with 3 arguments; Solaris seems to have just 2 args
  Check the existence of readdir_r and localtime_r; even though MySQL does check these too, we need our own check for Hot Backup code
os0file.c:
  Use re-entrant readdir_r where available
ut0ut.c:
  Make a function to use thread-safe localtime_r where available; that particular function was not called from anywhere, though