cmd/cgo: fail on v, err := C.fn when fn is a builtin function

We were already checking for _CMalloc, but in fact none of the
builtin functions support returning an error.

Fixes #67707

Change-Id: I0ee432a9f13ace472c3f36f641efc7d18eda0631
Reviewed-on: https://go-review.googlesource.com/c/go/+/589575
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/cmd/cgo/gcc.go

@@ -1601,8 +1601,8 @@ func (p *Package) rewriteName(f *File, r *Ref, addPosition bool) ast.Expr {
 			break
 		}
 		if r.Context == ctxCall2 {
-			if r.Name.Go == "_CMalloc" {
+			if builtinDefs[r.Name.Go] != "" {
-				error_(r.Pos(), "no two-result form for C.malloc")
+				error_(r.Pos(), "no two-result form for C.%s", r.Name.Go)
 				break
 			}
 			// Invent new Name for the two-result function.

src/cmd/cgo/internal/testerrors/errors_test.go

@@ -127,6 +127,7 @@ func TestReportsTypeErrors(t *testing.T) {
 		"issue33061.go",
 		"issue50710.go",
 		"issue67517.go",
+		"issue67707.go",
 	} {
 		check(t, file)
 	}

src/cmd/cgo/internal/testerrors/testdata/issue67707.go

@@ -0,0 +1,15 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+import "C"
+
+func F() *C.char {
+	s, err := C.CString("hi") // ERROR HERE: no two-result form
+	if err != nil {
+		println(err)
+	}
+	return s
+}