Force ftruncate for shared memory objects on FreeBSD
Created by: sghctoma
FreeBSD does not allow to use posix_fallocate
on shared memory objects.
I also think that this function should not be used here anyways, since shared memory objects are not regular files, and posix_fallocate
should give an ENODEV error if the fd refers to a non-regular file. At least that is my understanding of the POSIX specification.