Hello

i am again. Hope you still like reading mail from me.  ;)
Frank suggested using shell builtin instead of '\which'.

To my experience this noticeable speeds thinks up, which  ;)
is logically since changing '\which foo' to 'builtin which foo' 
reduces filesystemseeks by 50%.
Since 'builtin which foo' is zsh specific this resulted in quite a big patch
linewise.
So if you are interested here is the updated patch for check4progs().

Regards,
Thilo