C2Rust fails to translate GCC/Clang vector typedef with initializer list (`vector_size(16)`)

[lynae99]

C2Rust fails to transpile a valid C program using the GCC/Clang vector_size extension.
The program defines a vector type via attribute((vector_size(16))) and initializes a vector value using an initializer list. During transpilation, C2Rust skips the vector typedef due to unsupported CType::Vector, and then fails to translate main with Unknown vector init list.
C2Rust also still emits an incomplete Rust file that does not compile because main_0 is missing.
Reproducer

#include <stdint.h>

int main(void) {
    uint32_t counter = 0;
    uint32_t old1 = __atomic_fetch_add(&counter, 5, __ATOMIC_SEQ_CST);
    uint32_t old2 = __atomic_fetch_add(&counter, 3, __ATOMIC_SEQ_CST);

    typedef uint32_t v4ui __attribute__((vector_size(16)));
    v4ui atomic_results = {old1, old2, counter, 0};

    return 0;
}

Observed Behavior
C2Rust reports:

Transpiling test.c
error: Skipping declaration Some(Typedef { name: "v4ui", typ: CQualTypeId { qualifiers: Qualifiers { is_const: false, is_restrict: false, is_volatile: false }, ctype: CTypeId(694) }, is_implicit: false, target_dependent_macro: None }) due to error: Unsupported type Vector(CQualTypeId { qualifiers: Qualifiers { is_const: false, is_restrict: false, is_volatile: false }, ctype: CTypeId(695) }, 4)

error: Failed to translate main: Unknown vector init list: (Elaborated(CTypeId(696)), 4)

Environment

• c2rust version: v0.21.0
• platform: Ubuntu 24.04
• Rust: nightly-2022-08-08
• Clang version: 17.0.6