[Bug tree-optimization/85725] strchr and strstr of a one-element array with a non-empty string can be assumed to return null

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85725

--- Comment #2 from Andreas Schwab <schwab@linux-m68k.org> ---
The C standard defines a string as "a contiguous sequence of characters
terminated by and including the first null character" (7.1.1).