default or selected kernelversion does not have config value CONFIG_IP_DCCP_ACKVEC.
Result is shown for kernelversion 5.3.7

CONFIG_IP_DCCP_ACKVEC (not configurable)

configname: CONFIG_IP_DCCP_ACKVEC

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>The DCCP Protocol (EXPERIMENTAL)
└─>IP_DCCP_ACKVEC
In linux kernel since version 2.6.17 (release Date: 2006-06-17)