Rollup merge of #132216 - klensy:c_uint, r=cuviper

correct LLVMRustCreateThinLTOData arg types

`LLVMRustCreateThinLTOData` defined in rust as
```rust
    pub fn LLVMRustCreateThinLTOData(
        Modules: *const ThinLTOModule,
        NumModules: c_uint,
        PreservedSymbols: *const *const c_char,
        PreservedSymbolsLen: c_uint,
    ) -> Option<&'static mut ThinLTOData>;
```
but in cpp as
```cpp
extern "C" LLVMRustThinLTOData *
LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules, int num_modules,
                          const char **preserved_symbols, int num_symbols) {
```

(note `c_unit` vs `int` types). Let it be actually `size_t`.

Also fixes return type of `LLVMRustDIBuilderCreateOpLLVMFragment` to uint64_t as other similar functions around, which should be correct, i assume.

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -503,9 +503,9 @@ fn thin_lto(
         // upstream...
         let data = llvm::LLVMRustCreateThinLTOData(
             thin_modules.as_ptr(),
-            thin_modules.len() as u32,
+            thin_modules.len(),
             symbols_below_threshold.as_ptr(),
-            symbols_below_threshold.len() as u32,
+            symbols_below_threshold.len(),
         )
         .ok_or_else(|| write::llvm_err(dcx, LlvmError::PrepareThinLtoContext))?;