Fix for BSDI 4.0


Docs/manual.texi:
  Added MySQL AB information
configure.in:
  Fix for BSDI 4.0
myisam/mi_rprev.c:
  Fixed problem with concurrent inserts and read-previous
mysys/mf_format.c:
  Fix for BSDI 4.0
sql/handler.cc:
  Fixed type