US law on re-exporting crypto software?

An article in the current issue of the German journal `Datenschutz und Datensicherheit' claims that exporting crypto software from anywhere outside the US to a third country violates US law if the software contains (only marginal amounts of) US-developed code, such as a C standard library, and that anyone distributing crypto software that has been compiled with an American compiler had better not visit the United States. Is that true?