This is safe because the keyboard layout tables and standard virtual
key code assignments have all already been done.  This is necessary
because some X11 keyboard mappings (e.g. Greek keyboard layout on a
Mac) are full of non-Latin keysyms.

Restore availability of vkeys prior to VK_OEM_8.  That's safe now that OEM
vkeys are assigned in a separate loop after standard OEM vkey assignments
have been made.

e3ca5765 removed this call because we don't
need it to tell if the context is valid, but we still need it to actually make
the context current.