On error, asprintf returns -1 and the contents of the string
pointer is undefined. In the rest of the libvirt code,
the virAsprintf wrapper takes care of that.
Check the return value and report a generic error, since we
purposefully avoid linking to virutil.
Some of the examples make use of asprintf and strtol functions (to keep
things simple) which are prohibited to use within our code (enforced by
syntax-check). Therefore besides adding some examples, this patch also updates
cfg.mk to exclude examples directory from asprintf and strtol rules, as well as
updates .gitignore to exclude all the new admin binaries created in the
'examples' dir.
Signed-off-by: Erik Skultety <eskultet@redhat.com>