Asterisk 13.1 - json.c ‘JSON_PRESERVE_ORDER’ undeclared

In trying to install the latest certified Asterisk (certified-asterisk-13.1-current.tar.gz) , using

[code]contrib/scripts/install_prereq install we find that json.c and json.h source files are inconsistent.
This seems a rather major problem. How can anyone use this Asterisk release?

PLEASE If anyone has successfully installed Asterisk 13.1, please let me know.

./configure
make[/code]
We get the following errors:

[CC] json.c -> json.o json.c: In function ‘ast_json_set_alloc_funcs’: json.c:195:2: warning: implicit declaration of function ‘json_set_alloc_funcs’ [-Wimplicit-function-declaration] json.c: In function ‘ast_json_object_iter_at’: json.c:516:2: warning: implicit declaration of function ‘json_object_iter_at’ [-Wimplicit-function-declaration] json.c:516:2: warning: return makes pointer from integer without a cast [enabled by default] json.c: In function ‘ast_json_object_iter_set’: json.c:532:2: warning: implicit declaration of function ‘json_object_iter_set_new’ [-Wimplicit-function-declaration] json.c: In function ‘dump_flags’: json.c:541:20: error: ‘JSON_PRESERVE_ORDER’ undeclared (first use in this function)
After looking around, including asterisk-13-current.tar.gz, I can’t find the definition anywhere.

Any and all help will be appreciated.