Merge topic 'automoc-silence-warnings' into release-3.24

fc8628389f automoc: avoid more compiler warnings in linker-warning-silencing code

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !7617

Source/cmQtAutoMocUic.cxx

@@ -2183,6 +2183,9 @@ void cmQtAutoMocUicT::JobMocsCompilationT::Process()
     content += "// No files found that require moc or the moc files are "
                "included\n"
                "void " +
+      functionName +
+      "();\n"
+      "void " +
       functionName + "() {}\n";
   } else {
     // Valid content