On mips-yeeloong, build with -march=loongson2f when this flag is available (GCC >= 4.4). * conf/Makefile.common [COND_mips_yeeloong] (CFLAGS_PLATFORM): Remove `-march=mips3'. * configure.ac: For mips-yeeloong, add -march=loongson2f if available, or otherwise add -march=mips3.