csdk: fix minimal linux tests

csdk: fix minimal linux tests

Update to current API, and make them build by default.

Those samples files are good candidates
 to illustrate C API in plain C and not C++,
 specially for systems without recent g++ (ie: Tizen:2.2-)

Change-Id: I22e18903037a249e1dce4d29c2580ffe865caf50
Signed-off-by: Philippe Coval <philippe.coval@osg.samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/9515
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Habib Virji <habib.virji@samsung.com>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>
Reviewed-by: Ziran Sun <ziran.sun@samsung.com>