User Answer 101:
Okay, rankings.qc must be added to progs.src. Adding files to progs.src
was covered in lesson I (making of func.qc) and II (merging reaperbot 
files with v1.06 of QuakeC). This means it was covered twice. As I said
in the tutorials, you have to remember what you've learned from 
previous lessons. If rankings.qc is not added to progs.src then 
obviously all the ranking code (including the clientInitMaxClients 
function) will not be compiled into the program. 

Additionally, function prototypes for functions like Infront will have
to be added to func.qc file as well. Function prototypes were covered
in lesson #1. Recall that these function prototypes have to be 
declared (or at least the function itself defined) before actually 
calling the function. You will get an error if neither of these two 
criterias are satisfied. 

One more time, these two criterias are:
a) function prototypes have to be declared before using the function
b) function itself have to be defined before using the function

One of the above criterias have to be satisfied. Botit_th.qc and 
func.qc contain numerous examples of function prototypes. There is 
a reason for these files being compiled right after defs.qc. These 
function prototypes are declared long before the functions themselves 
are called. If it wasn't obvious before, the order in which the files
are compiled is important. This was mentioned in lesson #1 as I 
recall. I will repeat, the ORDER is important. In progs.src, the 
first file on the list is defs.qc. What does this mean? Well, it 
means that defs.qc is compiled first. Again, the function prototypes
or the function definition must appear BEFORE you use the function. 
If function prototypes or function definitions or both are in one 
file, what does that mean? Well, it means that the logic is very 
simple to follow. If this file is compiled early, then this means 
you will not have to worry about unknown value errors for those 
functions. Again, as I said, the order is important.

Furthermore, you also need a copy of btsk23.zip as stated in each 
part of the lesson. Rankings.qc is found in that file. 

Finally, yes, moving the function prototype or simply making 
another one in func.qc is the correct way to go. For example, 
having "float (entity targ) infront;" somewhere in the beginning 
of func.qc will be a good idea. It doesn't matter how many function 
prototypes you have. You can have a hundred of them if you want. It 
will be a waste of time making so many prototypes for one function 
but it is still okay as long as at least one of the prototypes appear 
before the function is actually called. (Also, there is a maximum 
size in terms of number of statements your program can be so you may 
wish to limit the number of prototypes for one function.) That is 
why it is good practice to place all of your function prototypes in 
one file after defs.qc. That is why func.qc was created in the first 
place. iD did a silly thing by placing their function prototypes and 
even variable declarations all over the place. You saw first-hand how 
annoying that is.