only make append & push const on Rust 1.83+

Author: Freax13

src/structures/gdt.rs

@@ -193,7 +193,8 @@ impl<const MAX: usize> GlobalDescriptorTable<MAX> {
     ///
     /// Panics if the GDT doesn't have enough free entries.
     #[inline]
-    pub const fn append(&mut self, entry: Descriptor) -> SegmentSelector {
+    #[rustversion::attr(since(1.83), const)]
+    pub fn append(&mut self, entry: Descriptor) -> SegmentSelector {
         let index = match entry {
             Descriptor::UserSegment(value) => {
                 if self.len > self.table.len().saturating_sub(1) {
@@ -245,7 +246,8 @@ impl<const MAX: usize> GlobalDescriptorTable<MAX> {
     }
 
     #[inline]
-    const fn push(&mut self, value: u64) -> usize {
+    #[rustversion::attr(since(1.83), const)]
+    fn push(&mut self, value: u64) -> usize {
         let index = self.len;
         self.table[index] = Entry::new(value);
         self.len += 1;