Avoid g++ warning about unhandled wxFONTFAMILY_XXX value in a switch.

Add wxFONTFAMILY_UNKNOWN case to the switch as it will allow us to be warned
if we add a new family in the future and forget to update this code to take it
into account.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63271 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/font.cpp

@@ -663,6 +663,10 @@ void wxNativeFontInfo::SetFamily(wxFontFamily family)
         case wxFONTFAMILY_DEFAULT:
             ff_family = FF_SWISS;
             break;
+
+        case wxFONTFAMILY_UNKNOWN:
+            wxFAIL_MSG( "invalid font family" );
+            return;
     }
 
     wxCHECK_RET( ff_family != FF_DONTCARE, "unknown wxFontFamily" );