darwin: Fix darwin int string mixing

func.go

@@ -287,7 +287,7 @@ func RegisterFunc(fptr any, cfn uintptr) {
 
 				for j, val := range args[i:] {
 					if val.Kind() == reflect.String {
-						ptr := strings.CString(v.String())
+						ptr := strings.CString(val.String())
 						keepAlive = append(keepAlive, ptr)
 						val = reflect.ValueOf(ptr)
 						args[i+j] = val

func_test.go

@@ -185,6 +185,18 @@ func TestABI(t *testing.T) {
 			t.Fatalf("%s: got %d, want %d", cName, res, expect)
 		}
 	}
+	{
+		const cName = "stack_8i32_3strings"
+		var fn func(*byte, uintptr, int32, int32, int32, int32, int32, int32, int32, int32, string, string, string)
+		purego.RegisterLibFunc(&fn, lib, cName)
+		buf := make([]byte, 256)
+		fn(&buf[0], uintptr(len(buf)), 1, 2, 3, 4, 5, 6, 7, 8, "foo", "bar", "baz")
+		res := string(buf[:strings.IndexByte(string(buf), 0)])
+		const want = "1:2:3:4:5:6:7:8:foo:bar:baz"
+		if res != want {
+			t.Fatalf("%s: got %q, want %q", cName, res, want)
+		}
+	}
 }
 
 func buildSharedLib(compilerEnv, libFile string, sources ...string) error {

testdata/abitest/abi_test.c

@@ -25,3 +25,7 @@ uint32_t stack_string(uint32_t a, uint32_t b, uint32_t c, uint32_t d, uint32_t e
     assert(strcmp(i, "test") == 0);
     return a | b | c | d | e | f | g | h;
 }
+
+void stack_8i32_3strings(char* result, size_t size, int32_t a1, int32_t a2, int32_t a3, int32_t a4, int32_t a5, int32_t a6, int32_t a7, int32_t a8, const char* s1, const char* s2, const char* s3) {
+    snprintf(result, size, "%d:%d:%d:%d:%d:%d:%d:%d:%s:%s:%s", a1, a2, a3, a4, a5, a6, a7, a8, s1, s2, s3);
+}