GCC configure: Error: Building GCC requires GMP 4.2 +, mpfr 2.3.1 + and MCM 0.8.0

Slave SVN checkout SVN: // gcc.gnu.org/svn/gcc/trunkget the latest gcccode, computation and compilation of the things about learning c++ 11, and the following problems occur during configure:
  Building GCC requires GMP 4.2 +, mpfr 2.3.1 + and MCM 0.8.0 +
   Http://www.multiprecision.org/mpc download mpc-0.9.tar.gz          
    Bytes
    Http://ftp.gnu.org/gnu/mpfr/download mpfr-3.1.0.tar.xz.
        Install GMP first. Decompress the GMP compressed package, get the source code folder gmp-5.0.1. Create a temporary compilation folder under the folder of the same level in this folder, named temp here. Start to configure the installation options, enter the temp folder, and enter the following command for Configuration:

../Gmp-5.0.1/configure -- prefix =/usr/local/gmp-5.0.1

    Make

    Sudo make install

    The installation methods of mpfr and nmpc are similar to those of GMP. Note that the dependency options of GMP and mpfr should be added during configuration. The detailed configuration command is as follows:

../Mpfr-3.1.0/configure -- prefix =/usr/local/mpfr-3.1.0 -- With-GMP =/usr/local/gmp-5.0.1

../Mpc-0.9/configure -- prefix =/usr/local/mpc-0.9 -- With-GMP =/usr/local/gmp-5.0.1 -- With-mpfr =/usr/local/mpfr-3.1.0

After these three libraries are installed, you can start to install GCC. 

    Of course, the three libraries that have just been compiled are required during the link.

    Export LD_LIBRARY_PATH = $ LD_LIBRARY_PATH:/usr/local/mpc-0.9/lib:/usr/local/gmp-5.0.1/lib:/usr/local/mpfr-3.1.0/lib

    Then the typical configure, make, and install three steps.

    .. /Gcc-4.7.2/configure -- prefix =/usr/local/gcc-4.7 -- enable-threads = POSIX -- disable-checking -- disable-multilib -- enable-versions ages = C, c ++ -- With-GMP =/usr/local/gmp-5.0.1 -- With-mpfr =/usr/local/mpfr-3.1.0 -- With-MPC =/usr/local/mpc-0.9

     Make

     Make check (optional)

     Sudo make install

    After a long wait:

 /Usr/local/gcc-4.7/bin/g + +-V
Use built-in specs.
Collect_gcc =/usr/local/gcc-4.7/bin/g ++
Collect_lto_wrapper =/usr/local/gcc-4.7/libexec/GCC/x86_64-unknown-linux-gnu/4.7.0/Lto-wrapper
Goals: x86_64-unknown-linux-gnu
Configuration :.. /gcc-4.7.2/configure -- prefix =/usr/local/gcc-4.7 -- enable-threads = POSIX -- disable-checking -- disable-multilib -- enable-versions ages = C, c ++ -- With-GMP =/usr/local/gmp-5.0.1 -- With-mpfr =/usr/local/mpfr-3.1.0 -- With-MPC =/usr/local/mpc-0.9
Thread model: POSIX
GCC version 4.7.0 20120113 (experimental) (GCC)

Start c ++ 11.

GCC configure: Error: Building GCC requires GMP 4.2 +, mpfr 2.3.1 + and MCM 0.8.0