Add wxGCD() helper function.

It is needed in wxMSW code and it looks like it could be useful to the library
users, so make it public.

See #16254.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77019 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Fix drawing on wxDC when using right-to-left layout in wxMSW.

Avoid integer overflow when setting wxDC scale. This affected (i.e. broke)
drawing in RTL but probably not only that.

Closes #16254.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77020 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Remove the files remaining from project-specific MSVS solutions.

These files are not used any more since r77008, there is only wx_setup.props
now.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77021 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775