Maybe simple...

sudo apt-get install gcc

... could be enough?

You can install gcc by running setup-x86.exe or setup-x86_64.exe again. The gcc package is in the Devel category:

Instead of running the script as ./run.sh, be sure that the first line of the script is #!/bin/bash and run it with bash run.sh.

Your line

Copygcc‬‬ ‫‪-g‬‬ ‫‪-m32‬‬ ‫‪-o‬‬ ‫‪skip‬‬ ‫‪skip.c

is ASCII broken. There are strange (invisible) characters before the spaces. Check it here.

Also, to run gcc with -m32 flag on, you need to install gcc-multilib first:

Copyapt-get install gcc-multilib

After running the second pass of gcc, ldd was pointing that gcc was using the host libraries. I didn't know how to solve it, so I simply ran the second pass of gcc again, but using the gcc binary of the last second pass without passing a CC variable.

Then ldd started to show that gcc was using the stuff under /tools.

But the binaries of binutils was also using the host libs, so I made again the second pass of binutils, without the CC, CXX, RANLIB or AR. This time it worked, I guess.

Now I am compiling glibc inside the chroot environment and so far I had no more problems. I don't know if what I did was right, but it did work.

It is a bad to update libraries from a testing PPA, unless you know what you're doing.

You're not getting any response for gcc --version because you don't have the gcc program with version 5.x available in current apt-repositories. The package-manager (here apt) have maintained two different packages for the same program but different versions 4.x and 5.x.

You can't get gcc-5 when you type sudo apt-get install gcc because it will try to get package named gcc not gcc-5 from the list of repositories defined by apt. Instead I would suggest you to get gcc-5 and then replace it with gcc or replacing an alias in ~/.bashrc file.

If you want to replace your gcc-5 with gcc you can try this gist link. Or mainly

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-5 g++-5

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 60 --slave /usr/bin/g++ g++ /usr/bin/g++-5

A less recommended option would be to add

alias gcc='gcc-5

in you ~/.bashrc. It will use gcc-5 when you use it from terminal and any other calls to gcc won't trigger gcc-5.