Fix build on some older versions of Rust

src/inner_connection.rs

@@ -261,7 +261,7 @@ impl InnerConnection {
         let tail = if c_tail.is_null() {
             0
         } else {
-            let n = unsafe { c_tail.offset_from(c_sql) };
+            let n = (c_tail as isize) - (c_sql as isize);
             if n <= 0 || n >= len as isize {
                 0
             } else {

src/types/from_sql.rs

@@ -136,7 +136,7 @@ impl FromSql for f64 {
 impl FromSql for bool {
     #[inline]
     fn column_result(value: ValueRef<'_>) -> FromSqlResult<Self> {
-        i64::column_result(value).map(|i| !matches!(i, 0))
+        i64::column_result(value).map(|i| i != 0)
     }
 }
 

src/vtab/series.rs

@@ -185,6 +185,7 @@ impl SeriesTabCursor<'_> {
         }
     }
 }
+#[allow(clippy::comparison_chain)]
 unsafe impl VTabCursor for SeriesTabCursor<'_> {
     fn filter(&mut self, idx_num: c_int, _idx_str: Option<&str>, args: &Values<'_>) -> Result<()> {
         let mut idx_num = QueryPlanFlags::from_bits_truncate(idx_num);
@@ -203,7 +204,6 @@ unsafe impl VTabCursor for SeriesTabCursor<'_> {
         }
         if idx_num.contains(QueryPlanFlags::STEP) {
             self.step = args.get(i)?;
-            #[allow(clippy::comparison_chain)]
             if self.step == 0 {
                 self.step = 1;
             } else if self.step < 0 {