strtoll is not defined when compiling with -std=c++03

[Gleb Popov]

Hello. I'm compiling following code

#include <stdlib.h>

int main()
{
 strtoll(0,0,0);
 return 0;
}

with -std=c++03 and getting:

tst.cpp:5:1: error: use of undeclared identifier 'strtoll'
strtoll(0,0,0);
^
1 error generated.

Preprocessing system headers with this flag shows that __LONG_LONG_SUPPORTED
isn't defined. Is this a bug?