FYI, the following all accomplish the same:
if (($bytetocheck >> $bittocheck) & 1)
if ($bytetocheck & (1 << $bittocheck))
if ($bytetocheck & $bit[$bittocheck])
if (vec($bytetocheck, $bittocheck, 1))

And in the interest of eliminating redundancy,

   if (($bytetocheck >> $bittocheck) & 1) {
      return 1;
   } else {
      return 0;
   }
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simplifies to any of the following:
return (($bytetocheck >> $bittocheck) & 1);
return ($bytetocheck & (1 << $bittocheck)) ? 1 : 0;
return ($bytetocheck & $bit[$bittocheck]) ? 1 : 0;
return vec($bytetocheck, $bittocheck, 1);

and the following, if you're only interested in returning a boolean value:
return ($bytetocheck & (1 << $bittocheck));
return ($bytetocheck & $bit[$bittocheck]);