Changes

solaris: fix strncpy truncation warnings
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

utils/info: add some build-time assertions for listing support bits
To make sure we don't forget to update this list.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

API: add HWLOC_TOPOLOGY_FLAG_IMPORT_SUPPORT to import support bits from
XML
Useful when you want to check whether binding/... is supported on the
distant platform. OMPI currently passes this info on the side of the
XML.
The support bits are still the local ones by default, but may be 
overwritten with the XML ones when this topology flag is set. The flag
doesn't change the fact that binding is disabled by default when loading
from XML.
Most tools enable this flag so that imported support bits are propagated 
in output XMLs.
Export support to XML may be disabled for debugging with
HWLOC_XML_SUPPORT_EXPORT=0.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

tests/xml: add some support bits in some test cases
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

API: add a misc support array for a "imported_support" feature
Passing HWLOC_TOPOLOGY_FLAG_IMPORT_SUPPORT won't import anything if the
XML comes from hwloc 2.2-. This new feature bit will be set on success
to import support.
The XML export doesn't contain that feature bit explicitly because it's
only meaningful locally. But it now contains a custom/fake feature bit
"custom.exported_support" that it always set on 2.3 export. Then the
importer knows whether support was unsupported in the exporter, or just
empty (likely rare, only on non-supported OS).
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>