Fix handling of Linux systems without struct statfs64

* acinclude.m4 (AC_STATFS64): New macro to check for struct statfs64.
* configure.ac: Call AC_STATFS64.
* file.c (printstatfs64, sys_statfs64, sys_fstatfs64): Compile only
  if struct statfs64 is available.

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
3 files changed