Fix compilation of wxSpinCtrlGenericBase when PCH are not used.

This fixes PCH-less compilation broken by r65043.

Closes #12259 (again).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65044 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/spinctlg.cpp

@@ -279,6 +279,12 @@ void wxSpinCtrlGenericBase::DoMoveWindow(int x, int y, int width, int height)
 // operations forwarded to the subcontrols
 // ----------------------------------------------------------------------------
 
+void wxSpinCtrlGenericBase::SetFocus()
+{
+    if ( m_textCtrl )
+        m_textCtrl->SetFocus();
+}
+
 bool wxSpinCtrlGenericBase::Enable(bool enable)
 {
     // Notice that we never enable this control itself, it must stay disabled