Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
FAILED: obj/third_party/crabbyavif/liblibyuv_sys.rlib 
"/usr/bin/python3" "../../build/rust/rustc_wrapper.py" --rustc=../../../../../../usr/bin/rustc --depfile=obj/third_party/crabbyavif/liblibyuv_sys.rlib.d --rsp=obj/third_party/crabbyavif/liblibyuv_sys.rlib.rsp -- -Clinker="clang++" --crate-name libyuv_sys ../../third_party/crabbyavif/src/sys/libyuv-sys/src/lib.rs --crate-type rlib --edition=2021 -Dunsafe_op_in_unsafe_fn -Cforce-unwind-tables=no -Crelocation-model=pic -Cdefault-linker-libraries -Zdep-info-omit-d-target -Zmacro-backtrace -Zremap-cwd-prefix=. -Zexternal-clangrt --color=always --target=x86_64-unknown-linux-gnu -Cembed-bitcode=no -Clto=no -Ccodegen-units=1 --cfg cr_rustc_revision=\"rustc\ 1.79.0\ \(129f3b996\ 2024-06-10\)\ \(Red\ Hat\ 1.79.0-3.el9_5\)\" -Copt-level=3 -Zallow-features= --emit=dep-info=obj/third_party/crabbyavif/liblibyuv_sys.rlib.d,link -o obj/third_party/crabbyavif/liblibyuv_sys.rlib LDFLAGS RUSTENV OUT_DIR=../../../../../../out/Release/gen/third_party/crabbyavif/crabbyavif_libyuv_sys
error: extern block cannot be declared unsafe
The error messages indicate that the rust compiler breaks with the error: extern block cannot be declared unsafe and the build failed