Undefined Symbols for Crate libafl-libfuzzer (with nix)

# Preface / IMPORTANT

> 1. You have verified that the issue to be present in the current `main` branch

Yes, I can confirm the issue on the current `main` branch.
I've provided a fully reproducible environment and a PoC at my repository: [fuzz-ciborium-poc](https://github.com/nausicaea/fuzz-ciborium-poc).

> Thank you for making LibAFL better!

Thank YOU for creating LibAFL in the first place! <3
Note that the error may be on my side. If I can provide more information, please let me know.

# Describe the Bug

Any attempts to build the fuzzing target (see my PoC above) fail with "Undefined symbols" errors. The following symbols are undefined:

* _LLVMFuzzerCustomCrossOver
* _LLVMFuzzerCustomMutator
* _libafl_main

Additional context clues see below.

# To Reproduce

1. Download the code from the linked repository: [fuzz-ciborium-poc](https://github.com/nausicaea/fuzz-ciborium-poc)
2. Install the [nix](https://nixos.org/download/#nix-install-macos) package manager
3. Navigate to the repository code and run `nix develop` to instantiate the development environment
4. Either build or run the fuzzing target with
`cargo fuzz build --fuzz-dir=. parse_cbor` or `cargo fuzz run --fuzz-dir=. parse_cbor`

# Expected behavior

I expect the build process to succeed.

# Additional context

## System Information

I am running an Apple MacBook Air M1 from 2020.

```
$ sw_vers
ProductName: macOS
ProductVersion: 15.7.3
BuildVersion: 24G419
```

## Nix Version

```
$ nix --version
nix (Nix) 2.31.2
```

## Build Output

```
$ cargo fuzz build --fuzz-dir=. parse_cbor
Compiling proc-macro2 v1.0.104
Compiling quote v1.0.42
Compiling unicode-ident v1.0.22
Compiling libc v0.2.179
Compiling serde_core v1.0.228
Compiling shlex v1.3.0
Compiling find-msvc-tools v0.1.6
Compiling equivalent v1.0.2
Compiling hashbrown v0.16.1
Compiling rustversion v1.0.22
Compiling winnow v0.7.14
Compiling zerocopy v0.8.31
Compiling indexmap v2.12.1
Compiling toml_writer v1.0.6+spec-1.1.0
Compiling toml_parser v1.0.6+spec-1.1.0
Compiling cfg-if v1.0.4
Compiling serde v1.0.228
Compiling arbitrary v1.4.2
Compiling syn v2.0.113
Compiling ciborium-io v0.2.2
Compiling serde_spanned v1.0.4
Compiling toml_datetime v0.7.5+spec-1.1.0
Compiling jobserver v0.1.34
Compiling toml v0.9.10+spec-1.1.0
Compiling cc v1.2.51
Compiling libfuzzer-sys v0.4.10
Compiling libafl_libfuzzer v0.16.0 (https://github.com/AFLplusplus/LibAFL.git#541f2ab6)
Compiling zerocopy-derive v0.8.31
Compiling serde_derive v1.0.228
Compiling half v2.7.1
Compiling ciborium-ll v0.2.2
Compiling ciborium v0.2.2
Compiling fuzz v0.0.0 (/Users/user/fuzz-ciborium)
error: linking with `cc` failed: exit status: 1
|
= note: "cc" "/Users/user/fuzz-ciborium/target/aarch64-apple-darwin/release/deps/rustc0F986c/symbols.o" "-Wl,-rpath,/lib/rustlib/aarch64-apple-darwin/lib" "-lrustc-nightly_rt.asan" "<2 object files omitted>" "/Users/user/fuzz-ciborium/target/aarch64-apple-darwin/release/deps/{libciborium-3802971a3dbfc522,libciborium_ll-1e428eb778db642d,libhalf-4d15cf6bcef657b0,libcfg_if-377cfced8ebf246a,libzerocopy-63c0177f1b8a37d7,libciborium_io-63e217a9a3e83d77,libserde-81112f74d620b63f,libserde_core-0ce0f116188b8bc4,liblibafl_libfuzzer-cbf6165bc4b5726e,liblibfuzzer_sys-bb2e3fceb8cc50fb,libarbitrary-ab00bc0412e9afeb}.rlib" "/lib/rustlib/aarch64-apple-darwin/lib/{libstd-*,libpanic_unwind-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,libcfg_if-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*,liblibc-*,librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-lc++" "-lSystem" "-lc" "-lm" "-arch" "arm64" "-mmacosx-version-min=14.0.0" "-L" "/Users/user/fuzz-ciborium/target/aarch64-apple-darwin/release/build/libafl_libfuzzer-5a9ac33ce1560295/out/libafl_libfuzzer/target" "-L" "/lib/rustlib/aarch64-apple-darwin/lib" "-o" "/Users/user/fuzz-ciborium/target/aarch64-apple-darwin/release/deps/parse_cbor-f47b4ddfbca59b2b" "-Wl,-dead_strip" "-nodefaultlibs"
= note: some arguments are omitted. use `--verbose` to show all linker arguments
= note: Undefined symbols for architecture arm64:
"_LLVMFuzzerCustomCrossOver", referenced from:
_libafl_targets_has_libfuzzer_custom_crossover in liblibafl_libfuzzer-cbf6165bc4b5726e.rlib(ea708c7824d36062-libfuzzer.o)
_libafl_targets_libfuzzer_custom_crossover in liblibafl_libfuzzer-cbf6165bc4b5726e.rlib(ea708c7824d36062-libfuzzer.o)
"_LLVMFuzzerCustomMutator", referenced from:
_libafl_targets_has_libfuzzer_custom_mutator in liblibafl_libfuzzer-cbf6165bc4b5726e.rlib(ea708c7824d36062-libfuzzer.o)
_libafl_targets_libfuzzer_custom_mutator in liblibafl_libfuzzer-cbf6165bc4b5726e.rlib(ea708c7824d36062-libfuzzer.o)
"_libafl_main", referenced from:
_main in liblibafl_libfuzzer-cbf6165bc4b5726e.rlib(ea708c7824d36062-libfuzzer.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

error: could not compile `fuzz` (bin "parse_cbor") due to 1 previous error
Error: failed to build fuzz script: ASAN_OPTIONS="detect_odr_violation=0" RUSTFLAGS=" -Cpasses=sancov-module -Cllvm-args=-sanitizer-coverage-level=4 -Cllvm-args=-sanitizer-coverage-inline-8bit-counters -Cllvm-args=-sanitizer-coverage-pc-table -Cllvm-args=-sanitizer-coverage-trace-compares --cfg fuzzing -Cllvm-args=-simplifycfg-branch-fold-threshold=0 -Zsanitizer=address -Cdebug-assertions -Ccodegen-units=1" "cargo" "build" "--manifest-path" "./Cargo.toml" "--target" "aarch64-apple-darwin" "--release" "--config" "profile.release.debug=\"line-tables-only\"" "--bin" "parse_cbor"
```