minor code cleanups

src/header/stdio/mod.rs

@@ -578,10 +578,9 @@ pub unsafe extern "C" fn fopen(filename: *const c_char, mode: *const c_char) ->
 
     helpers::_fdopen(fd, unsafe { CStr::from_ptr(mode) })
         .map(Box::into_raw)
-        .map_err(|err| {
+        .inspect_err(|err| {
             // TODO: guard type
             if let Ok(()) = Sys::close(fd) {}; // TODO handle error
-            err
         })
         .or_errno_null_mut()
 }

src/header/stdio/printf.rs

@@ -610,9 +610,8 @@ impl<'a, T: c_str::Kind> Iterator for PrintfIter<'a, T> {
         self.format = first_percent.split_first().expect("must be %").1;
 
         let mut peekahead = self.format;
-        let index = pop_index(&mut peekahead).map(|i| {
+        let index = pop_index(&mut peekahead).inspect(|i| {
             self.format = peekahead;
-            i
         });
 
         // Flags: