afl binary cannot be built

[yongmandooo]

after "cargo afl build", there is an error.

Compiling png-afl v0.2.0 (/home/kym000131/fuzzing_set/Rust/image-png/png-afl) error: declaration of ano_mangle` function
--> src/main.rs:11:1
|
11 | #[no_mangle]
| ^^^^^^^^^^^^
|
= note: the linker's behavior with multiple libraries exporting duplicate symbol names is undefined and Rust cannot provide guarantees when you manually override them
note: the lint level is defined here
--> src/main.rs:2:11
|
2 | #![forbid(unsafe_code)]
| ^^^^^^^^^^^

error[E0308]: mismatched types
--> src/main.rs:19:9
|
19 | let (info, mut reader) = decoder.read_info().map_err(|| ())?;
| ^^^^^^^^^^^^^^^^^^ ------------------------------------ this expression has type Reader<&[u8]>
| |
| expected Reader<&[u8]>, found (_, _)
|
= note: expected struct Reader<&[u8]>
found tuple `(, _)``

I think there is a problem in png-afl/src/main.rs

[whtsht]

Since detect_odr_violations=0 is now set by default, you can delete the code that causes the first error.

The second mismatched types error easy to fix.