Did you install the build dependencies? https://sources.debian.org/src/opendkim/2.11.0%7Ebeta2-1/debian/control/#L5-L8
strlcpy and strlcat are provided by libbsd.
Did you install the build dependencies? https://sources.debian.org/src/opendkim/2.11.0%7Ebeta2-1/debian/control/#L5-L8
strlcpy and strlcat are provided by libbsd.