overlaycheck: readline() on closed filehandle $fh at /usr/bin/overlaycheck line 361 & 516

```
# overlaycheck -v
* This isn't a Linux repository
* Failed to open 'overlays/README'
readline() on closed filehandle $fh at /usr/bin/overlaycheck line 361.
* Failed to open 'overlays/Makefile'
readline() on closed filehandle $fh at /usr/bin/overlaycheck line 516.
Failed

```
Compiled on Alpine/musl in case that matters