Remove all uses of Function::with_name_signature

The current main branch of Cranelift changed it's signature. Removing
it's use is the easiest way to deal with this.

Author: bjorn3

src/allocator.rs

@@ -78,7 +78,7 @@ fn codegen_inner(
         let callee_func_id = module.declare_function(&callee_name, Linkage::Import, &sig).unwrap();
 
         let mut ctx = Context::new();
-        ctx.func = Function::with_name_signature(ExternalName::user(0, 0), sig.clone());
+        ctx.func.signature = sig.clone();
         {
             let mut func_ctx = FunctionBuilderContext::new();
             let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);
@@ -116,7 +116,7 @@ fn codegen_inner(
     let callee_func_id = module.declare_function(callee_name, Linkage::Import, &sig).unwrap();
 
     let mut ctx = Context::new();
-    ctx.func = Function::with_name_signature(ExternalName::user(0, 0), sig);
+    ctx.func.signature = sig;
     {
         let mut func_ctx = FunctionBuilderContext::new();
         let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);

src/main_shim.rs

@@ -74,7 +74,7 @@ pub(crate) fn maybe_create_entry_wrapper(
         let main_func_id = m.declare_function(main_name, Linkage::Import, &main_sig).unwrap();
 
         let mut ctx = Context::new();
-        ctx.func = Function::with_name_signature(ExternalName::user(0, 0), cmain_sig);
+        ctx.func.signature = cmain_sig;
         {
             let mut func_ctx = FunctionBuilderContext::new();
             let mut bcx = FunctionBuilder::new(&mut ctx.func, &mut func_ctx);