As it turns out, on my 32bit ARM machine size_t is not the same
size as ULL. However, @length argument for both functions is type
of size_t but it's treated as ULL - for instance when passed to
qemuMonitorJSONMakeCommand(). The problem is that because of
"U:size" the virJSONValueObjectAddVArgs() expects an ULL argument
but on the stack there are size_t and char * arguments (which
coincidentally add up to size of ULL). So the created command has
only two arguments "val" and incorrect "size" and no "path" which
is required.

I've tried to find other occurrences of this pattern but at the
rest of places where size_t is used it tracks size of an array so
that's safe.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
ACKed-by: NPeter Krempa <pkrempa@redhat.com>