games/libretro-fbneo: mark BROKEN

../../burner/libretro/libretro.cpp:372:19: error: non-const lvalue reference to type 'basic_ostringstream<...>' cannot bind to a temporary of type 'basic_ostringstream<...>'
                                option_name = SSTR( "DIPSWITCH " << dipswitch_core_options.size() );
                                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../burner/libretro/retro_common.h:10:19: note: expanded from macro 'SSTR'
                  ^                                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Approved by:	portmgr blanket
Reported by:	pkg-fallout