Added a new utils.c wrapper err_gzclose and changed gzclose calls to use it.
Put in some more err_fflush calls before files being written are closed.
Made err_fflush call fsync. This is useful for remote filesystems where
errors may not be reported on fflush or fclose as problems at the server
end may only be detected after they have returned. If bwa is being used
only to write to local filesystems, calling fsync is not really necessary.
To disable it, comment out #define FSYNC_ON_FLUSH in utils.c.
Rob Davies
Heng Li