New issue by loreb on void-packages repository

https://github.com/void-linux/void-packages/issues/33699

Description:
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### System

* xuname:  
  Void 5.13.19_1 x86_64-musl GenuineIntel uptodate rFF
* package:  
  util-linux-2.37.2_1

### Expected behavior
The program prints "Would you like to edit (filename) now [y/n]? ", I see the question and reply

### Actual behavior
The program shows nothing, I type "y" and *then* it prints the question - there should be a `fflush(stdout)` between printf and fgets in login-utils/vipw.c:354, or to be even safer set stdout to unbuffered right on program startup.

### Steps to reproduce the behavior
as root, run vipw or vigr on a musl system using /etc/shadow, modify anything and see