Add Xinuos SCO OpenServer 5.0.7/3.2 support

The license donation for OpenServer 5.0.7/3.2 by Xinuos Inc. helped to
make this commit possible.
Add README for Xinuos SCO OpenServer 5.0.7/3.2
Bump version to 20140314

* Add SCO OpenServer 5.0.7/3.2 support
* Replace _DIR with _DIR_H in dir.h, because SCO OpenServer 5.0.7/3.2 has _DIR
  macro in dirent.h
Updated devel/bmake to 20140314
Update to 20140314

* Add SCO OpenServer 5.0.7/3.2 support
Updated pkgtools/bootstrap-mk-files to 20140314
Add SCO OpenServer 5 and 6 support, 6 support is not tested yet.
Add SCO OpenServer 5.0.7/3.2 support
Fix build under SCO OpenServer 5.0.7/3.2
Fix PATH_MAX value for SCO OpenServer 5.0.7/3.2.
It is 1024 really.
Fix build under SCO OpenServer 5.0.7/3.2
Set MAXPATHLEN
Fix build under SCO OpenServer 5.0.7/3.2
Fix build under SCO OpenServer 5.0.7/3.2
It has no S_ISSOCK.
Do not preserve owner of installed files.
This causes multiple failures of Ruby gems in FreeBSD bulk builds.
(Besides, it is unclear whether it is actually needed or wanted.)
Add builtin gettext-lib support under SCO OpenServer 5.0.7/3.2.
But it is very old and is not recommended.
Add a builtin.mk file for xauth - dropbear uses this, and right now, it's
way too reliant on the build host for this value.
Only 1 package in the tree uses a buildlink dependency on libtomcrypt
(security/dropbear), so bump the BUILDLINK_API_DEPENDS to reflect the
current value of the package.
Use the xauth builtin.mk to find the location on the target system.

Just use the security/libtomcrypt/buildlink3.mk now the
BUILDLINK_API_DEPENDS has been updated.
Fix build under SCO OpenServer 5.0.7/3.2
and add workaround for empty result of nl_langinfo(CODESET).
This workaround is needed for devel/gtexinfo.
Uses libexecinfo (fixes build on FreeBSD 10).