translate-c: regression when translating mutually recursive C typedef'ed structs

### Zig Version 0.16.0-dev.1485+0f1a6ae94 ### Steps to Reproduce and Observed Behavior I use the C library `LibBF` in a project, whose header translates fine on 0.15.2 On master, compilation fails with `.zig-cache/o/<hash>/cimport.zig:193:5: error: dependency loop detected` I narrowed it down to the follow repro (the LibBF library has more types involved in the dependency loop, but this is enough to reproduce): ```c // NOTE: this is an anonymous struct, and that seems to cause problems typedef struct { struct bf_context_t *ctx; } bf_t; // NOTE: this struct, on the other hand, is tagged typedef struct bf_context_t { bf_t val; } bf_context_t; ``` `zig-master translate-c repro.zig` generates problematic code: ```zig // error: dependency loop detected pub const bf_t = bf_t; pub const struct_bf_context_t = extern struct { val: bf_t = @import("std").mem.zeroes(bf_t), }; pub const bf_context_t = struct_bf_context_t; ``` `zig-0.15.2 translate-c repro.zig` generates code that compiles: ```zig pub const struct_bf_context_t = extern struct { val: bf_t = @import("std").mem.zeroes(bf_t), }; pub const bf_t = extern struct { ctx: [*c]struct_bf_context_t = @import("std").mem.zeroes([*c]struct_bf_context_t), }; pub const bf_context_t = struct_bf_context_t; ``` ### Expected Behavior Generation of correct Zig source code when translating mutually recursive C structs.