Merge branch 'fallocate' of https://github.com/t-8ch/util-linux

* 'fallocate' of https://github.com/t-8ch/util-linux:
  tests: (swaplabel) don't create test image with truncate(1)
  fallocate: require posix_fallocate() from libc
  fallocate: drop syscall() fallback for fallocate()
  build: simplify checks for fallocate() and posix_fallocate()