Compability for older json-c releases

Compability for older json-c releases

commit 0b63a8b7cfb7 ("Check json-c libversion, recover commit d127537")
broke building on older releases when using 'make'.
As the original issue was about json-c not being able to parse full 64
numbers this patch separates out 32 and 64 json objects and adds a warning
if an overflow occurs on older json-c releases.

Signed-off-by: Hannes Reinecke <hare@suse.de>