This indir shebang thing is handled in toke.c

I found here that indir was a program to call indirectly other programs:

If I recall correctly, 'indir' was a program designed to indirectly 
execute other programs.  My recollection is that it was supposed to be
+ 
particularly useful in setuid situations where the OS didn't natively 
provide you much help, and/or perhaps in situations where the OS kerne
+l 
limited you to 32 character command lines.

> Personally I wouldn't object to the removal of this exec feature. Bu
+t
> at the very least shouldn't we document that "indir" thing ?

I don't think indir is actively maintained, and we don't recommend
doing setuid scripts this way anymore either, so removing the 'indir' 
special case is probably appropriate.
[download]

L*