Auto merge of #66378 - rkruppe:revert-pr-65134, r=pnkfelix

Revert #65134

To stop giving people on nightly reasons to `allow(improper_ctypes)` while tweaks to the lint are being prepared.

cc #66220

src/librustc_codegen_llvm/back/write.rs

@@ -240,7 +240,9 @@ impl<'a> Drop for DiagnosticHandlers<'a> {
     }
 }
 
-fn report_inline_asm(cgcx: &CodegenContext<LlvmCodegenBackend>, msg: &str, cookie: c_uint) {
+unsafe extern "C" fn report_inline_asm(cgcx: &CodegenContext<LlvmCodegenBackend>,
+                                       msg: &str,
+                                       cookie: c_uint) {
     cgcx.diag_emitter.inline_asm_error(cookie as u32, msg.to_owned());
 }
 

src/librustc_codegen_llvm/llvm/mod.rs

@@ -87,7 +87,6 @@ pub struct RustString {
 }
 
 /// Appending to a Rust string -- used by RawRustStringOstream.
-#[allow(improper_ctypes)]
 #[no_mangle]
 pub unsafe extern "C" fn LLVMRustStringWriteImpl(sr: &RustString,
                                                  ptr: *const c_char,