strtok behaviour when uninitialized

[Florian Weimer]

On 02/11/2018 08:32 PM, Zack Weinberg wrote:
> With my security hat on, I would like glibc to define as many cases of
> undefined behavior as possible -- as prompt, guaranteed crashes.
> Defining the behavior as anything else leads to people relying on
> whatever the definition is, but leaving it as "whatever the code
> happens to do"_also_  leads to people relying on the actual behavior,
> plus it leaves room for exploits.

But in the case of strtok, the more relevant undefined behavior is that 
it's not thread-safe.  There's a fairly large number of libraries which 
reference both pthread_create and strtok, which is rather sad.

Thanks,
Florian