Check for statx support
I was testing the new version of master with statx and it failed in my machine.
Looking at the documentation:
statx() was added to Linux in kernel 4.11; library support was added
in glibc 2.28.
I have kernel 5.3.0-51-generic with ldd (Ubuntu GLIBC 2.27-3ubuntu1) 2.27.
I've included some #ifdefs to check for support for statx.