wig: create a BorrowChecker just to get things compiling. Needs fixing.

crates/wasi-common/wig/src/wasi.rs

@@ -468,9 +468,17 @@ pub fn define_struct_for_wiggle(args: TokenStream) -> TokenStream {
                                 }
                             };
                             let mem: WasiMemory = mem.into();
+                            // FIXME:
+                            // Currently, none of the wasi-common functions will re-enter the guest, so
+                            // creating a BorrowChecker here ensures there is just one per the
+                            // WebAssembly memory. I'd like a wasmtime expert to show me how to
+                            // create a BorrowChecker once per Store, and access it in this
+                            // context, though.
+                            let bc = wiggle::BorrowChecker::new();
                             wasi_common::wasi::#module_id::#name_ident(
                                 &mut my_cx.borrow_mut(),
                                 &mem,
+                                &bc,
                                 #(#hostcall_args),*
                             ) #cvt_ret
                         }