if ((ssize_t) want < 0)
as_fatal ("string buffer overflow");
#if GCC_VERSION >= 3004
- max = (size_t) 1 << (CHAR_BIT * sizeof (want) - __builtin_clzl (want));
+ max = (size_t) 1 << (CHAR_BIT * sizeof (want)
+ - (sizeof (want) <= sizeof (long)
+ ? __builtin_clzl ((long) want)
+ : __builtin_clzll ((long long) want)));
#else
max = 128;
while (want > max)