Handle multi-giga byte writes to files

Test cases that write 4Gb to a file at once would fail on
OS X and FreeBSD.

By running a simple test program on OS X (El Capitan 10.11.4/Darwin
15.4.0), I found that writev() can handle more than 4Gb of data, while
write() only can handle less than 2Gb. (Note that efile_drv.c will use
write() if there is only one element in the io vector, and writev() if
there is more than one.)

It is tempting to attempt to piggy-back on the existing mechanism
for segmenting write operations in efile_drv.c, but because of the
complex code I find it too dangerous, both from a correctness and
performance perspective.

Instead do the change in unix_efile.c, which is considerably
simpler.

0 files changed, 0 insertions, 0 deletions