fix linker errors: add tetra scene node stuff, and link libSDL.a
fix linker errors: add tetra scene node stuff, and link libSDL.a


kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1,kongr45gpen/bzflag-import-1