A problem on building GCC

[m9802119]

hello:

I tried to build tic6x cross compiler in recent days, but always fail.
this is my building step:
    cd build-binutils/
    ../binutils-2.22/configure --prefix=/usr/local/c6x/ --target=tic6x-elf
    make all
    make install
    cd .. 
    cd build-gmp/
    export PATH=$PATH:/usr/local/c6x
    export PATH=$PATH:/usr/local/c6x/bin
    ../gmp/configure --prefix=/usr/local/c6x/gmp
    ../gmp/configure --prefix=/usr/local/c6x/gmp
    make
    make install
    cd ..
    cd build-mpfr/
    ../mpfr/configure --prefix=/usr/local/c6x/mpfr --with-gmp=/usr/local/c6x/gmp
    make
    make install
    cd ..
    cd build-mpc
    ../mpc/configure --prefix=/usr/local/c6x/mpc --with-gmp=/usr/local/c6x/gmp --with-mpfr=/usr/local/c6x/mpfr --enable-static --disable-shared
    make
    make install
    cd ..
    cd build-gcc
    ../gcc-4.7.2/configure --target=tic6x-elf --prefix=/usr/local/c6x --enable-languages="c,c++" --with-newlib --with-header=../newlib-1.20.0/newlib/libc/include --with-gmp=/usr/local/c6x/gmp --with-mpfr=/usr/local/c6x/mpfr --with-   mpc=/usr/local/c6x/mpc
    make all-gcc
    make install-gcc
    cd ..
    cd build-newlib/
    export LD_LIBRARY_PATH=$LD_LIBRARY_PATH}:/usr/local/c6x/gmp:/usr/local/c6x/mpfr/lib:/usr/local/c6x/mpc/lib
    ln -s /usr/local/c6x/bin/tic6x-elf-gcc /usr/local/c6x/bin/tic6x-elf-cc
    ../newlib-1.20.0/configure --target=tic6x-elf --prefix=/usr/local/c6x/
    make all install
    cd ..
    cd build-gcc
    make all install

after these step I build cross compiler successful, but wen I compile .c file the error occur:
$ tic6x-elf-gcc helloworld.c
helloworld.c:1:16: error：stdio：No such file or directory

why ?
I build ARM cross compiler is no problem by following these step.

Thanks
Best Regards,

W.J. Wang