MFC r303955:
Restore "nat global" support. Now zero value of arg1 used to specify "tablearg", use the old "tablearg" value for "nat global". Introduce new macro IP_FW_NAT44_GLOBAL to replace hardcoded magic number to specify "nat global". Also replace 65535 magic number with corresponding macro. Fix typo in comments. PR: [[ https://bugs.freebsd.org/211256 | 211256 ]]