afx[cCd-] src dst add/remove code/Call/data/string reference

Usage: afx[-cCd?] [src] [dst] manage function references (see also ar?)

• afxc sym.main+0x38 sym.printf add code ref
• afxC sym.main sym.puts add call ref
• afxd sym.main str.helloworld add data ref
• afx- sym.main str.helloworld remove reference
• afxj