++AC_CACHE_CHECK([for useable fallocate],rsync_cv_have_fallocate,[
++AC_TRY_LINK([#include <sys/syscall.h>
++#include <sys/types.h>],
++[syscall(fallocate, 0, 0, 0, 0);],
++rsync_cv_have_fallocate=yes,rsync_cv_have_fallocate=no)])
++if test x"$rsync_cv_have_fallocate" = x"yes"; then
++ AC_DEFINE(HAVE_FALLOCATE, 1, [Define to 1 if you have the fallocate function and it compiles and links without error])
++fi
++