MFH: r494760 r495669

games/openbor: unbreak with GCC 4.2

cc1: error: unrecognized command line option "-Wno-unused-result"

source/gamelib/loadimg.o:(.text+0x1ce8): undefined reference to `builtin_unreachable'
source/gamelib/loadimg.o:(.text+0x2164): undefined reference to `builtin_unreachable'

Reported by: pkg-fallout
Approved by: ports-secteam blanket