Make wxUxThemeIsActive() available even in this case to fix compilation
in some places and add the unavoidable preprocessor checks in other
ones.
Closes#18207.
removing 'inline' did fix:
warning: 'virtual void wxSystemThemedControlBase::DoEnableSystemTheme(bool, wxWindow*)' redeclared without dllimport attribute after being referenced with dll linkage
but introduced
multiple definition of `wxSystemThemedControlBase::DoEnableSystemTheme(bool, wxWindow*)'.
The proposed form gets no complaints
wxSystemThemedControl allows to use the "system theme" (i.e. the theme used by
the system applications such as file manager and which can, surprisingly, be
different from the default one). Currently it is only implemented for wxMSW
and does nothing under the other platforms.
Use wxSystemThemedControl for wxDataViewCtrl, wxListCtrl and, optionally, if
wxTR_TWIST_BUTTONS style is specified, wxTreeCtrl to give them more native
appearance under MSW.
Closes#16414.