Use i64 to accomodate for device files' major and minor numbers

This is meant as the final step in fixing ogham#1126.

src/fs/fields.rs

@@ -194,8 +194,8 @@ pub enum Size {
 /// - <http://www.lanana.org/docs/device-list/devices-2.6+.txt>
 #[derive(Copy, Clone)]
 pub struct DeviceIDs {
-    pub major: u32,
-    pub minor: u32,
+    pub major: i64,
+    pub minor: i64,
 }
 
 

src/fs/file.rs

@@ -336,9 +336,11 @@ impl<'dir> File<'dir> {
         else if self.is_char_device() || self.is_block_device() {
             let device_ids = self.metadata.rdev();
 
+            // SAFETY: `major()` and `minor()` can return an unsigned integer
+            // of at most 32bits, so an `i64` is going to accomodate them well
             f::Size::DeviceIDs(f::DeviceIDs {
-                major: unsafe { major(device_ids) },
-                minor: unsafe { minor(device_ids) },
+                major: unsafe { major(device_ids) as i64 },
+                minor: unsafe { minor(device_ids) as i64 },
             })
         }
         else {