allow using wxEventLoopGuarantor when wxUSE_GUI==1
fixes wxOSX-Cocoa build when wxUSE_CONSOLE_EVENTLOOP==0
closes #14980


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76364 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775