GCC升级问题解决：configure: error: Building GCC requires GMP 4.2+, MPFR 2.4.0+ and MPC 0.8.0+.，mpfr2.4.0
如果遇到类似问题：
configure: error: Building GCC requires GMP 4.2+, MPFR 2.4.0+ and MPC 0.8.0+.，mpfr2.4.0
解决：
yum install gmp gmp-devel mpfr mpfr-devel libmpc libmpc-devel
