BSDi uses size_t * for the optlen arg to getsockopt, while other Unixes
use socklen_t *.


acconfig.h:
  - compatibility fix for BSDi (getsockopt optlen type)
configure.in:
  - compatibility fix for BSDi (getsockopt optlen type)
libmysql/libmysql.c:
  - compatibility fix for BSDi (getsockopt optlen type)
sql/mini_client.cc:
  - compatibility fix for BSDi (getsockopt optlen type)