This patch fixes assuming a 64-bit toolchain.
https://github.com/nicokoch/reflink/pull/5


--- reflink-0.1.3/src/sys/unix.rs	2019-04-02 16:13:06.000000000 +0200
+++ "reflink-0.1.3 (Kopie)/src/sys/unix.rs"	2023-06-29 09:47:26.867681403 +0200
@@ -7,7 +7,7 @@
     use std::os::unix::io::AsRawFd;
 
     // TODO is this equal on all archs? Just tested on x86_64 and x86.
-    const IOCTL_FICLONE: u64 = 0x40049409;
+    macro_rules! IOCTL_FICLONE { () => (0x40049409) };
 
     let src = fs::File::open(&from)?;
 
@@ -18,7 +18,7 @@
         .open(&to)?;
     let ret = unsafe {
         // http://man7.org/linux/man-pages/man2/ioctl_ficlonerange.2.html
-        libc::ioctl(dest.as_raw_fd(), IOCTL_FICLONE, src.as_raw_fd())
+        libc::ioctl(dest.as_raw_fd(), IOCTL_FICLONE!(), src.as_raw_fd())
     };
 
     if ret == -1 {