Helper function to compare the value of a PLIST_KEY node against a given value.
This function basically behaves like strcmp.
Parameters
keynode
node of type PLIST_KEY
cmpval
value to compare against
Returns
0 if the node's value and cmpval are equal, > 0 if the node's value is lexicographically greater than cmpval, or < 0 if the node's value is lexicographically less than cmpval.