r21552: Ensure to check for proto_exists before linking any binary. No make

r21552: Ensure to check for proto_exists before linking any binary.  No make
proto should be required before creating any binary from now on.

Remove proto_exists from the all, pam_smbpass, and pam_bindind rule.
(This used to be commit 95d22979743c94565d9d0bbb64eb1e9adeba10d3)