fseek
=====

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

Gnulib module: fseek

Portability problems fixed by Gnulib:

  * This function mistakenly succeeds on pipes on some platforms: mingw, MSVC 14.

Portability problems not fixed by Gnulib:

  * On Windows platforms (excluding Cygwin), this function does not set errno upon failure.

  * On platforms where long is a 32-bit type, fseek does not work correctly with files larger than 2 GB, even when the AC_SYS_LARGEFILE macro is used.  The fix is to use fseeko instead.