What does this statement really mean? I have seen the same wording in several NDAs.
The question of waiving the copyright of source code depends on the extent, if any, to which the code entails or reflects trademarks & confidential information the counterparty needs or needed to provide for implementation of its business rules (and finding that language in several NDAs means that either several lawyers regurgitate the exact same wording, or all such drafts you have seen happen to come from one same lawyer applying the same language over and over again).
The focus of the clause is the confidential information and trademarks, whence it would be quite a stretch to allege a priori that the clause implies the programmer's waiver of copyright of all his source code in the implementation.
Apropos of your mention of "unilateral", it should be pointed out that once the programmer accepts the clause it is binding. In other words, the clause cannot be voided merely on grounds that it was introduced by the customer/employer. This applies no matter how badly it limits the programmer's interests. Hence the importance for the programmer to timely reject the clause if he considers it unfair or inappropriate.