So what is your proposal how to fix this:

src/httpc.c:777:24: error: comparison of unsigned expression < 0 is always false [-Werror,-Wtautological-compare]
  csize = hc->hc_csize < 0 ? 0 : hc->hc_csize;
          ~~~~~~~~~~~~ ^ ~
1 error generated.
make: *** [/Volumes/src/tvheadend/build.darwin/src/httpc.o] Error 1