I can't install gcc 9

[Jonathan Wakely]

On Wed, 3 Jul 2019 at 09:20, Dorian ROSSE <dorianbrice@hotmail.fr> wrote:
>
> The system installing of gcc is the Following :
>
> ./config.guess
>
> x86_64-pc-linux-gnu
>
> When I launch
>
> ../gcc-9.1.0/configure
>
> required isl version is 0.15 or later
>
> The following languages will be built: c,c++,fortran,lto,objc
>
> *** This configuration is not supported in the following subdirectories:
>
>      gnattools gotools target-libada target-libhsail-rt target-libphobos target-zlib target-libgo                                                                                                     target-libffi target-liboffloadmic
>
>     (Any other directories should still work fine.)
>
> configure: creating ./config.status
>
> config.status: creating Makefile
>
> Now I run Following :
>
> ../gcc/configure --enable-languages=c,c++,go && make && make install

You're running configure twice, with different options. Why?

Why is it ../gcc-9.1.0/configure the first time, and ../gcc/configure
the second time?