QHostInfo: fix lookupHost() signature immediately

... and not just for Qt 7.

Found in API-Review.

Amends dd50d58af2.

[ChangeLog][QtNetwork][QHostInfo] The lookupHost() static function now
takes const QObject* receivers (was: (non-const) QObject*).

Pick-to: 6.7
Change-Id: I22b11e06cfba4e96975239cabed8b379cf3f4fa4
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/network/compat/removed_api.cpp

@@ -9,6 +9,16 @@ QT_USE_NAMESPACE
 
 #if QT_NETWORK_REMOVED_SINCE(6, 7)
 
+#include "qhostinfo.h"
+
+// static
+int QHostInfo::lookupHost(const QString &name, QObject *receiver, const char *member)
+{
+    const auto *r = receiver;
+    return lookupHost(name, r, member);
+}
+
+
 #include "qnetworkreply.h"
 
 QByteArray QNetworkReply::rawHeader(const QByteArray &headerName) const

src/network/kernel/qhostinfo.cpp

@@ -221,9 +221,12 @@ static int nextId()
     \note There is no guarantee on the order the signals will be emitted
     if you start multiple requests with lookupHost().
 
+    \note In Qt versions prior to 6.7, this function took \a receiver as
+    (non-const) \c{QObject*}.
+
     \sa abortHostLookup(), addresses(), error(), fromName()
 */
-int QHostInfo::lookupHost(const QString &name, QT7_ONLY(const) QObject *receiver, const char *member)
+int QHostInfo::lookupHost(const QString &name, const QObject *receiver, const char *member)
 {
     if (!receiver || !member) {
         qWarning("QHostInfo::lookupHost: both the receiver and the member to invoke must be non-null");

src/network/kernel/qhostinfo.h

@@ -48,7 +48,10 @@ public:
     void setLookupId(int id);
     int lookupId() const;
 
-    static int lookupHost(const QString &name, QT7_ONLY(const) QObject *receiver, const char *member);
+#if QT_NETWORK_REMOVED_SINCE(6, 7)
+    static int lookupHost(const QString &name, QObject *receiver, const char *member);
+#endif
+    static int lookupHost(const QString &name, const QObject *receiver, const char *member);
     static void abortHostLookup(int lookupId);
 
     static QHostInfo fromName(const QString &name);