chore: checkpoint before Python removal

vendor/libm/src/math/frexpf.rs

@@ -0,0 +1,22 @@
+#[cfg_attr(assert_no_panic, no_panic::no_panic)]
+pub fn frexpf(x: f32) -> (f32, i32) {
+    let mut y = x.to_bits();
+    let ee: i32 = ((y >> 23) & 0xff) as i32;
+
+    if ee == 0 {
+        if x != 0.0 {
+            let x1p64 = f32::from_bits(0x5f800000);
+            let (x, e) = frexpf(x * x1p64);
+            return (x, e - 64);
+        } else {
+            return (x, 0);
+        }
+    } else if ee == 0xff {
+        return (x, 0);
+    }
+
+    let e = ee - 0x7e;
+    y &= 0x807fffff;
+    y |= 0x3f000000;
+    (f32::from_bits(y), e)
+}