I have added my own fuzzer into

osquery/osquery/main/harnesses/CMakeLists.txt

right below the other fuzz instructions as

generateOsqueryFuzzHarness(osqueryfuzz-fu0 <http://fu0.cc|fu0.cc>)

- fu0.cc is on the same dir as other .cc fuzzers. I tried to build it like

lamba@ubuntu:~/osquery/build$ cmake --build . --target osqueryfuzz-fu0
make: *** No rule to make target 'osqueryfuzz-fu0'.  Stop.