This allows to construct a font based on the parent window font instead of
either fully specifying all font parameters or basing it on a standard font.
Closes#14632.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72572 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775