wget http://ftp.tsukuba.wide.ad.jp/software/gcc/releases/gcc-4.9.2/gcc-4.9.2.tar.bz2tar -xjvf gcc-4.9.2.tar.bz2cd gcc-4.9.2.tar.bz2./configure

configure: error: Building GCC requires GMP 4.2+, MPFR 2.4.0+ and MPC 0.8.0+.Try the --with-gmp, --with-mpfr and/or --with-mpc options to specifytheir locations.  Source code for these libraries can be found attheir respective hosting sites as well as atftp://gcc.gnu.org/pub/gcc/infrastructure/. 

http://ftp.tsukuba.wide.ad.jp/software/gcc/infrastructure/gmp-4.3.2.tar.bz2http://ftp.tsukuba.wide.ad.jp/software/gcc/infrastructure/mpfr-2.4.2.tar.bz2http://ftp.tsukuba.wide.ad.jp/software/gcc/infrastructure/mpc-0.8.1.tar.gz

./configuremakemake install

The following languages will be built: c,c++,fortran,java,lto,objc*** This configuration is not supported in the following subdirectories:     gnattools target-libada target-libgo target-libbacktrace    (Any other directories should still work fine.)checking for default BUILD_CONFIG... bootstrap-debugchecking for --enable-vtable-verify... no/usr/bin/ld: crt1.o: No such file: No such file or directorycollect2: ld returned 1 exit statusconfigure: error: I suspect your system does not have 32-bit developement libraries (libc and headers).
If you have them, rerun configure with --enable-multilib. 
If you do not have them, and want to build a 64-bit-only compiler, rerun configure with --disable-multilib.

./configure --disable-multilib

make

checking whether build environment is sane... configure: error: newly created file is older than distributed files!Check your system clockmake[2]: *** [configure-stage1-zlib] Error 1make[2]: Leaving directory `/root/gcc-4.9.2‘make[1]: *** [stage1-bubble] Error 2make[1]: Leaving directory `/root/gcc-4.9.2‘make: *** [all] Error 2

ntpdate cn.pool.ntp.org

make

checking for suffix of object files... configure: error: in `/root/gcc-4.9.2/x86_64-unknown-linux-gnu/libgcc‘:configure: error: cannot compute suffix of object files: cannot compileSee `config.log‘ for more details.make[2]: *** [configure-stage1-target-libgcc] Error 1make[2]: Leaving directory `/root/gcc-4.9.2‘make[1]: *** [stage1-bubble] Error 2make[1]: Leaving directory `/root/gcc-4.9.2‘make: *** [all] Error 2

yum install libgcc.i686

make

make install

gcc -v Using built-in specs.COLLECT_GCC=gccCOLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/x86_64-unknown-linux-gnu/4.9.2/lto-wrapperTarget: x86_64-unknown-linux-gnuConfigured with: ./configure --disable-multilibThread model: posixgcc version 4.9.2 (GCC)