fixes 64 bit to 32 warnings, see #16329

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@77698 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Request hardware accelerated GL under OS X only if it's available.

Otherwise wxGLCanvas creation just fails completely when it isn't, e.g. when
running inside a VM.

Closes #16555.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@77699 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775