strtoull
========

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/strtoull.html

Gnulib module: strtoull

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: HP-UX 11.11, MSVC 9.

  * This function does not parse the leading 0 when the input string is "0x" and the base is 16 or 0 on some platforms: Minix 3.3, mingw, MSVC 14.

  * This function does not parse binary integers (with a 0b or 0B prefix) when the base is 2 or 0 on many platforms.

Portability problems not fixed by Gnulib: