Restore, but deprecate, LOGFONT conversion functions in wxMSW

Even though these functions were declared in a header called private.h,
some code outside the library still used them, notably the popular
wxPdfDocument library.

So partially revert 72a225924d and these
functions back, and just mark them as deprecated for now.

src/msw/fontutil.cpp

@@ -264,3 +264,21 @@ wxFontEncoding wxGetFontEncFromCharSet(int cs)
 
     return fontEncoding;
 }
+
+// ----------------------------------------------------------------------------
+// Deprecated wxFont <-> LOGFONT conversion functions
+// ----------------------------------------------------------------------------
+
+#if WXWIN_COMPATIBILITY_3_0
+
+void wxFillLogFont(LOGFONT *logFont, const wxFont *font)
+{
+    *logFont = font->GetNativeFontInfo()->lf;
+}
+
+wxFont wxCreateFontFromLogFont(const LOGFONT *logFont)
+{
+    return wxFont(wxNativeFontInfo(*logFont));
+}
+
+#endif // WXWIN_COMPATIBILITY_3_0