yum install libmpc-devel mpfr-devel gmp-devel
cd ~/Downloads curl ftp://ftp.mirrorservice.org/sites/sourceware.org/pub/gcc/releases/gcc-4.9.2/gcc-4.9.2.tar.bz2 -O
tar xvfj gcc-4.9.2.tar.bz2
cd gcc-4.9.2
./configure --disable-multilib
make -j 4
make install