tabular_output: enable compilation on Windows

Add the required directives to the makefile.

Change-Id: I7a6e612b37cbf1f6cb61faf55d7c248f8f85808c
Reviewed-on: http://gerrit.openafs.org/10328
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>